Microcosmos is a natural history of the unseen beings upon whom we depend every moment for survival: the microbes. Margulis, who is currently Distinguished University Professor in the Department of Geology at the University of Massachusetts, did undergraduate work in biology and received her PhD in Genetics. She worked with James Lovelock on developing the Gaia theory, which posits that the earth can be regarded as a sort of super-organism. In Microcosmos we see all aspects of her education and sensibilities -- a close attention to scientific detail and a "big picture" approach to how living entities coexist.

In the introduction she lays out her philosophy about life on earth, for which she was roundly criticized by many reductionist scientists. In the past, she writes, all life on Earth was traditionally studied as being merely a prelude to the appearance of humans. Now, overwhelming evidence suggests that microbes (one-celled organisms) not only inhabit every known living thing on earth, they are also indispensable to the survival of all living things. They, not human beings, are the most important beings on the planet.

Furthermore, in opposition to one of the most accepted tenets of Neo-Darwinism, Margulis states that life did not colonize the planet by competition so much as by networking. Cooperation between one-celled creatures led, over billions of years, to the evolution of beings such as ourselves, who possess the capability for self-conscious awareness. Our human consciousness, of which we are so proud, "may have been born of the concerted capacities of millions of microbes that evolved symbiotically to become the human brain."

Strong words! Yet, Margulis sets forth compelling evidence in the remainder of her book to support her bio-philosophical ideas. Along the way, we learn many amazing things. For instance, we get a perspective on what upstart newcomers we are: the continents we inhabit now appeared in their present locations only in the last tenth of a percent of Earth's history. We learn that bacteria invented genetic engineering. Thus, when ultraviolet light damaged early microbes' DNA, the creatures produced repair enzymes to remove the damaged portions and copy new replacement DNA. This is a natural form of gene splicing.

Sometimes, the DNA used in gene splicing was borrowed from neighboring bacteria of different strains, thus affording these critters a prodigious adaptability. This borrowing still goes on today. Through intermediaries, two very different bacteria can share genetic information. Why is this important? Because it allows the distribution of genetic information in the microcosm with a speed "approaching that of modern telecommunications--if the complexity and biological value of the information being transferred is factored in." This speed makes bacteria the biosphere's first responders in dealing with planetary changes.

In responding to change, bacteria end up altering and shaping their environments. Few people realize that the entire earth's atmosphere, which we depend on for our life's breath, was created, and is maintained, by microbes. This is a good thing to remember next time you feel like spraying down your bathroom or kitchen with anti-microbial spray. Our fear of bacteria is misplaced. Yes, some are harmful to us, but most are beneficial. Indeed they are a lot more helpful to us than we are to the rest of the planet!

This book isn't an easy read, but it will broaden one's outlook on our place in the natural world. Even if bacteria are not in the end responsible for the intricacies of our human brain and consciousness, we still owe them many debts. This book unveils the smallness of humans before the vast and minute workings of nature, and encourages a sense of humility before the greater Life that surrounds us.

Well. I would not have been terribly suprised had this turned out to be a great book. Nonetheless, I was pleasently so when I realized I actually enjoyed it as much as Microcosmos. I don't know how much of which author went into what--and that does not really seem to matter. The ideas flow easily and evenly--the biology is straightforward and understandable, and the chronology seems (at least for me) easy to follow. In my humble opinion, another excellent book, and a must for any real thinkers library. I have mine..where's yours?

A theory of everything book begins with the big bang and concludes either with modern humanity or our someday-to-be colonization of the stars. This offering by the mother/son team of Margulis and Sagan is now 16 years old and a bit ragged around the edges, but still an informative read. Margulis' claim to fame is the symbiosis theory now standard fare in college biology texts. It states that mitochondria and chloroplasts were once free living bacteria that became trapped in other bacteria, giving rise to eukaryotic cells. Margulis also hypothesizes that flagella were once free living spirochetes. Her emphasis on nonhuman life (mostly prokaryotic) as the dominant biological mover is refreshing and she takes us on a virtual tour of the inception of life on this planet, accompanied by a nifty geological time chart, through to some pretty farout scenarios of how life might escape our one day to be dead sun. She goes as far as to posit Homo photosyntheticus, or plant people, who have chloroplasts in their skin and eat light.

Most of us think of evolution as darwinian survival of the fittest, with cheetahs and gazelles in a competitive arms race for survival. This book more accurately portrays selective mechanisms as predominately cooperative and microbially based. Certainly we would not be here to contemplate at all were it not for our ancestor bacteria, and this mocrobial history is written into our very genome. Approximately 5 % of our genome is putatively defunct viruses for example.

Chapter 2 is a pretty good synopsis of prebiotic chemistry. Chapter 4 gives a good definition on the disparateness between sex and reproduction. Chapter 5 shows how bacteria are essentially one ubiquitous species that casually transfer genes horizontally. Chapter 10 gives a great account of meiosis and mitosis and their permutations in the two biological domains, as well as fairly debunking the notion that the value of sex is its superior ability to offer genetic variability over fissioning prokaryotes. In Chaper 11 she gives a good account of how plants and animals (veritable colonies of bacteria) came to colonize the land on earth. Humans enter the scene in chapter 12 via neotony. The last chapter, chapter 13, goes out on a variety of speculative limbs in conclusion.

While this book contains its share of factual errors, probably due to its age, its a well crafted popsci book that makes geotemporal biology accessible to the lay reader.

This is an outstanding and very readable book on the world of microbes. Beautifully written and filled with insights, it should be required reading for biology students. I couldn't put it down and I hated biology in high school! I takes you from the beginnings of our planet to the present time, showing the reader the crucial role of microbes in the creation and maintenance of all life. This book will also be of interest to any serious student of the Gaia hypothesis. Read it and you will never think of cells, bacteria and viruses the same way again. You will come away with a humbling and enlightened view on man's place in a world created, dominated, and maintained by microbes.

For those of you who don't know, Lyn Margulis is the ex wife of the late Carl Sagan (prior to Ayn Druian) and Ms. Margulis is Dorian Sagan's mother.Together, they make an excellent writing team.

If you're one of those who has felt worried that the earth might not survive what we're doing to it, then worry no longer! We, as a species which has brought 'wholesale ecological carnage' to the planet may not survive, but the earth surely will! What soon emerges from this insightful book is that humankind is a relatively young species, still 'vulnerable, error-prone.' Humans are not seen as the dominant species - the pinnacle of evolution - but as one of the still immature species. The real players are the species that have been here the longest, the bacteria. 'Even nuclear war would not be total apocalypse, since the hardy bacteria underlying life on the planetary scale would doubtless survive it.'

Margulis and Sagan relegate Darwin to a secondary place within the order of things: the most powerful and important changes in evolution happen not through mutation - as Darwin would have it - but through symbiosis, '...the merging of organisms into new collectives, proves to be a major power of change on Earth.' In particular oxygen-breathing bacteria merged with other organisms to enable oxygen-based life on the once alien surface of this hydrogen filled planet. 'The symbiotic process goes on unceasingly.' 'Fully ten percent of our own dry body weight consists of bacteria - some of which.... we cannot live without.' That's an estimation of ten thousand billion bacteria each!

Imagine a droplet of water with a membrane holding the water in place and allowing certain nutrients in. This is a simplified description of how it is imagined the first becteria came into being. The book offers a fascinating history of the evolution of life on our planet. This is a wonderful story full of fantastic developments spanning thousands of millions of years. Every now and then we are reminded by the authors that none of it could have taken place or could be happening now were it not for the metabolic abilities of bacteria. It gives a really eye-opening account of bacterial sex with the insight that all bacteria, all over the planet, are really part of one organism because they are all able to exchange genetic information. For instance it's thought that bacteria obtained their now well-known resistence to penicillen from their bacterial cousins in the soil. But also, you begin to get the impression that perhaps it's the bacteria which have used every means possible and are now using us too to spread onto the land and all over the planet and beyond from their original wet home in the ocean. Humans are defintely relegated to a secondary place within something much, much bigger that is (consciously?) evolving.

This is a fascinating book which has radically changed the way I perceive life and the universe. I read it with great excitement and completed it with a new awe for those minute beings, the bacteria, which have, until now, had a very bad press. The best non-fiction book I've read this year.

This is a fairly well written book, and the author does a credible job of trying hard to link together and postulate connections between unrelated and spurrious data. So, if you are a naturalist and a fan of poorly writen and campy sci-fi, this book is for you. Read it at parties and try to appear intellectual. Truly a hilariously bad attempt at trying to seek, desparately, naturalistic origins of human intelligence. The only proof being the authors and fans of the book illustrate that perhaps they do in fact have the intelligence of lizards. Proof after all?

"The only book on our origins that will be read 100 years on". Surely not? But this book hides the nuts and bolts of a new answer to an old question that will reshape the sciences of human nature - below I give details and let you decide whether this is indeed the next big thing.

But first that old question: what turned the human brain -- initially evolved 100,000 years ago to be, and only be, a smart hunter-gatherer -- into a brain that in each of us is superfitted for our hi-tech modern life. The problem is an embarrassment to science. No neurologist or paleoanthropologist can explain why your brain so obviously not evolved to read this, does so, like with so many other nonevolved modern skills, with such great finesse. Human evolution lacks foresight and so could have made no preparation. It is a big question. Evolutionary psychology offers no explanation. But the genius of Skoyles and Sagan provides a clear and plausible account.

Before summarizing what that is, a criticism. You start off thinking this is Dragons of Eden: The 25 year Sequel -- but Carl was a science populariser; this book, though averagely well written, lacks illustrations and has rather too many notes and references - more a book for getting out of the library than buying for a holiday read. That said, you soon realize that, with all respect to Carl Sagan, this book is much more important than anything he wrote.

Request, even buy, and get it, for its explanation of that old problem. Chapter 14 lays out its core story one which fits together the jig-saw puzzle pieces that the authors have earlier assembled in chapters 3-13 that describe the latest findings in neuroscience and paleoanthropology. The synthesis they offer is a radically novel, reductive and unexpectedly powerful new neurobiological and anthropological theory of symbolism.

Two theories intertwine. First, that the radical changes in cognition and behavior that make us unique are piggybacked upon earlier evolved primate cognitions and emotions. Symbols - stand-ins - they show are at the heart of the human revolution. Evolved primate cognitions process innate inputs - but culturally transmitted nonevolved signs can co-opt their innate processes. The co-optation just needs (and humans are good at this) the ability to learn abstract associations. When symbols co-opt innate ape psychology, it is like an engine being put into a new chassis -- ape psychology is refitted thus into doing something radically new -- human psychology with all its nonevolved cognitions. For example, the core process of fear in apes uses the innate inputs of snakes, spiders, angry faces and blood. But humans can uniquely hock on novel sign inputs such as swastikas, the radiation sign, evil eyes and the thoughts of God - and so use them to power the radically new behaviors that make us cultural.

But what enables humans to put a new culturally derived 'chassis' on the ape brain? Here is their second theory. Symbolic co-optation arose from the prefrontal cortex working memory acting as an abstract association "catalyst" upon neural plastic networks. Many molecules would meet too rarely to react unless another molecule - a catalyst puts them together. The same with the neural connections that underlie the abstract associations of symbolic cognition - the 'catalyst' in this case being the working memory of the prefrontal cortex that can 'tutor' new neural links. And the new associations that it creates happen thanks to the recently discovered phenomena of neural plasticity which allows old cognitions to rewire to do radically new tasks. The theory uses bits of already established science. It is theoretical innovation at its best - clear "mechanical" sound processes with no hand waved 'dues ex machine' processes. Simple - yet overlooked - perhaps because of the breadth of knowledge they bring together -- by those whose business it is to invent such ideas.

You have to read the argument to appreciate its explanatory power. For a hint, consider how our social attachment is both different and not different from that of other apes. Both ape and human attachment depends upon the same limbic processes. But in nonhuman apes, the inputs to such process arise entirely from the actual physical presence of another individual -hugging, grooming, facial reactions, and the feel of warmth. Symbolic culture puts new a chassis on these limbic processes by adding new inputs such as wedding rings, name changes, and rituals. In doing so, the new 'symbolic chassis' enables our ape limbic brain to create human specific forms of social bonds - such as those of marriage, with distant kin, the supernatural and society. This idea is simply an act of genius since reveals how neuroscience and grammatology so easily fit under anthropology and even such fields as cultural studies.

Further, the authors make the breakthrough of showing how what is a transient and private emotion in other apes could by a simple scientifically analyzable process become one that in humans is resistant to separation (symbols can stand-in for missing people and relationships with them), and embedded in communities (symbols allow societies to define relationships and so build up social complexity). One hates the phrase "scientific revolution" or "new paradigm" but these authors have done it - the core problem of our origins has been found. They call their idea, the missing link of human evolution. And they are right.

The resulting approach is not only elegant, simple and powerful - but the stuff of which I bet further science discoveries will be born. It is the first book that can be properly called 'neuropaleoanthropology'. It is the beginning of something big. The oddly titled book - a wrong title if there ever was one -- does what evolutionary psychology should have done, but has not - reveal the biological dragons under our anthropological Eden.

When Dorion Sagan first told me about his then "upcoming project" with John Skoyles, I decided then and there that it was a book I would order, as I have found his books to be of extreme interest, covering interesting topics, and fantastically well written. Although I had heard of Dr. Sloyles, I was not familiar with his research, or his writing. A dreadful error on my part that I will indeed remedy. I am not a biologist, nor a neuroscientist, although I have a great deal of fascination, and have devoted many years of study toward both subjects. Being a student of life, so to speak, I have read a very large number of books over the past 30 years (despite being Dyslexic) including all of Carl Sagan's as well as Dorion Sagan's books. My home library has been moved four times to different rooms in my home of ever-increasing dimension. As I will now be adding everything I can find by John Skoyles to that list, it may just be moving again. His writing (no doubt influenced by the linear pace of Dorion Sagan) makes for a clear, precise, and articulate examination of intelligence, what is was; what it may be; and perhaps most importantly--where it just might be going. These amazing ideas are not simply laid at one's feet, to be examined "willy-nilly" but are instead couched in the "Carl Sagan" mode of using clear, concise, real life examples, and are phrased with us "regular folks" in mind. I have read a number of "similar books" or perhaps I should say books on similar topics. They were difficult to wade through at best, often used difficult verbiage, and were, in use a term "thick." It was as if one needed a Masters in psychology just to follow the author (I have one and I still got lost!). For a clear, concise look at the history, complexity, and study of the many aspects of "intelligence" one need look no further than this book: it is an entire library unto itself. The very fact that Dr. Skoyles is Dyslexic, and was considered "the bottom of the class" shows again how society often cannot recognize pure genius. There are insufficent "stars" to give this book it's just rating, thus five must do.

"What Is Life?" is an illuminating & expansive reconstruction of the bacterial evolution of life on Earth. Combining rigorous science, mythology, history, poetry, stories, sketches, wit, captivating writing, & arresting photography, Margulis & Sagan examine Professor Margulis' theory of endosymbiosis.

Needless to say, Dr. Margulis has left me speechless. I cannot post here an adequate review of this book because I can't find the words to express what this book has done to my beliefs.

Others have done it much better. For the best review, read Piero Scaruffi's 1999 review titled "Lynn Margulis, Dorion Sagan: What is Life? (Simon & Schuster, 1995)." Scaruffi does Dr. Margulis justice. Like many other readers, on the other hand, he is unfair to Dorion Sagan as his mother's co-writer. Nothing conveys to the ordinary reader the wonder & vast scope of the world of science better than stimulating prose. With it, I am able to "get" very quickly otherwise confounding stuff. Thanks to Sagan, I am able to learn all over again long-forgotten facts like the structure & function of DNA & RNA. I like Sagan's off-hand style & acidic wit. His eccentricity makes his science books fun to read.

Dr. Lynn Margulis - Maverick Microbiologist Extraordinaire!

Dorion Sagan - You Rock!

I was as enthralled as other reviewers with the amazing facts in this book. My favorite: bacteria don't age; they can die from accidental causes but "programmed death" started with eukaryotes. The authors show that death is necessary for organisms (like us) that practice meiotic cell division.

But this book is far more than a random collection of facts. Margulis and her collaborators do an amazing job of assembling an understandable model of life using parts carefully selected from a vast body of biological knowledge. While a one-sentence definition is still elusive, the reader builds up a picture of life's most pertinent characteristics, as exhibited by the truly astounding diversity of living things on this planet. By the time I finished, I was satisfied that the authors had answered the question.

You don't need to be a biologist to understand and enjoy this book. Its beauty is that the greatest scientific thinking on the most complex topics has been presented in common english, with necessary scientific terms explained as they are introduced. If you are intrigued by the question of life, I doubt there's a more complete, accurate, understandable, and enjoyable answer available than this book.

This book is written with great intelligence and subtlety. I'm an engineer, and it has been about thirty years since my last biology class. I'm not even sure what compelled me to update my knowledge in this field. I suppose the title "What is Life?", got my attention, as I found this title to be somewhat audacious. Let's face it, "What is Life?", is the supreme question, and any author who ventures in this direction is walking a tight-rope of controversy.

I can honestly say I learned a lot from this book, as I've underlined just about every page. It has so many fascinating insights about the evolution of bacteria into living organisms. As the authors acknowledge, scientists today do not yet understand all the fundamental biological questions - but it sure seems they are headed in the right direction.

Quoting from p. 218, "The facts of life, the stories of evolution, have the power to unite all people". Although I doubt that we can ever "unite all people", I believe that this book will be appreciated by readers who are looking for modern and rational explanations to some existential questions, within the context of biology.

I came upon this book while doing some research into the Gaia hypothesis and found it interesting, especially the autobiographical essays. However, I still think the Gaia hypothesis is a little extreme when formulated as if organisms have a reason to sacrifice their individual survival for the benefit of "Gaia" as a whole. When this anti-natural selection aspect is removed, Gaia says only that organisms have effects on their environment and can evolve feedback systems, which isn't really anything new. It was a fascinating and revolutionary idea - and I do respect it for "thinking outside the box", so to speak - but I just don't see it working out. And attacking reductionism never got anybody anywhere...sometimes things must be understood at their most fundamental level.

No scientist of our times has more right than Lynn Margulis to crow about her once-ridiculed but now-vindicated discoveries, such as the cell symbiosis hypothesis. Yet, for all her enthusiasm in promoting her now widely respected triumphs and her new, still-to-be-tested hypotheses, Margulis does not gloat. She is gracious with her opponents and generous in sharing credit with her grad students and other collaborators. One of the volume's most attractive features is that it summarizes the development to date of the views of James Lovelock and herself, on their widely debated and very influential Gaia hypothesis. We are treated to numerous fascinating anecdotes about the making of such a controversial theory, and about its reception (not always very polite, let alone friendly) by the community of "objective" scientists. The real gems of the book, however, are two autobiographical pieces by Margulis, "Sunday with J. Robert Oppenheimer" and "The Red Shoe Dilemma," and a third article "Big Trouble in Biology." In the first, we witness the encounter between the precocious sixteen year old future scientist Margulis and the recently deposed titan of atomic physics and "father of the atomic bomb" at his home in Princeton. The second piece offers Margulis's retrospective on what it meant to be a woman during our times who tried to be a great scientist, as well as a great wife and mother. Her spare use of words throws sharply into relief the realities still facing young women who would make a career in the sciences. Every one of those young women should read this book, and especially "The Red Shoe Dilemma." For any critics of the excesses of late-twentieth century reductionism in the life sciences, "Big Trouble in Biology" will be a call to arms, albeit a very thoughtful and provocative one. Lynn Margulis is no anti-science crackpot; nor is she a latter-day vitalist. But from one of the most successful practitioners in the methodology of reductionism, this heart-felt call for LOOKING at whole, living organisms and marvelling at their living qualities is a challenge that demands serious attention.

Acquiring Gnomes is an attempt to support the theory of symbiogenesis, the idea that organisms evolve by exchanging genes and as a result of symbiosis relationships, such as lichen. The authors are the leading experts in the field of symbiosis, and this shows in this well done work. The major strong point of the work is it explains in detail what biologists have known for years but often do not admit publicly, namely that evolution by the accumulation of small mutations has not been supported by either laboratory or field research. The authors also show that Darwin has been almost a god for over a century, yet his work was neither original (and he failed to credit those he plagiarized his ideas from - see p. 27) and his classic 1859 book The Origin of Species is "laced with hesitancies, contradictions, and possible prevarication" (p. 26). Having shown neo-Darwinism is now effectively dead, the authors make an excellent case for their own theory of the origin of species. The only problem is they demonstrate that many lower level organisms have probably exchanged genetic material throughout history, yet this does not explain its origin, only its spread. We are still left with the question "where did the genome information come from in the first place?" It may be best to admit that we do not know (and present theories do not explain this problem) so that future scientists are encouraged to look for the source instead of discouraging research by teaching students that we know the source when we do not. As a college teacher for over 35 years now, in my classes I stress what we do not know in my field (molecular biology) with the hope that my students may be inspired to find some of the answers. This book is a good place to begin. The authors also show that anyone who questions Darwin "are often dismissed as if they were Christian fundamentalist zealots or racial bigots" (p. 19). This is tragic.

Lynn Margulis has been a maverick all her life. Early in her career she shocked her biological colleagues by arguing that the mitochondria that power our cells and the chloroplasts that let plants transform solar into chemical energy once were free-living bacteria. As soon as scientists could isolate and decode the scraps of DNA in those vital organelles, they found that she was right. Margulis went on to develop her Serial Endosymbiosis Theory, which attempted to trace the development of all creatures with nucleated cells, from yeasts to humans, to a series of genetic mergers between different kinds of organisms. According to Margulis, all the familiar family trees of life, which show only diverging branches, are wrong. Ancient roots and current branches cross and merge to produce new species. To Margulis, nature is far more promiscuous and much more creative than most biologists dream.

Her new book, Acquiring Genomes: A Theory of the Origins of Species, extends and deepens that argument. Margulis sets out to prove that new species rarely if ever appear as the result of mutation, isolation, genetic drift, or population bottlenecks--the meat and potatoes of neo-Darwinism. Instead she maintains that the major engine of evolutionary change, the source of most of the new forms that natural selection edits, is symbiogenesis--the acquisition of whole genomes as the result of symbiotic associations between different kinds of organisms. (Knowing that some people will seize on her thesis as an attack on the theory of evolution as a whole, Margulis makes it clear that she fully supports Darwin's great discovery of the mechanism of natural selection. She simply thinks that neo-Darwinists have failed to recognize the enormous creative power of genomic mergers.)

Readers who are familiar with Margulis' earlier works will recognize her vivid, personal and sometimes impressionistic writing style. I found this book, co-authored by her son, Dorion Sagan, to be clear and accessible. Starting with Chapter 9, where Margulis presents her latest ideas on the symbiotic origin of the nucleus itself, things get a bit more technical. Margulis makes every effort to help readers through the thicket of important, but at times tongue-twisting terms, and supplements explanations in the text with an excellent glossary. Margulis also presents the findings of several other researchers whose work supports or relates closely to her own.

Readers may or may not close the book convinced that Margulis is right and the neo-Darwinists are wrong. But they will come away with a vastly deeper understanding of the pervasive nature and power of the microbial world, and of symbiosis. Margulis reveals a hidden side of nature, in which microbes have generated most if not all of life's metabolic machinery, in which vastly different life-forms consort in a myriad of ways, and in which the acquisition of entire genomes provides the raw material for great evolutionary leaps. Anyone with a deep interest in biology will gain important insights from "Acquiring Genomes."

Robert Adler, author of Science Firsts: From the Creation of Science to the Science of Creation (Wiley & Sons, 2002).

Lynn Margulis and Dorion Sagan continue their series of books on highlighting Margulis's evolving and elaborative theory on evolution. Margulis, with her symbiosis concept, is science's only significant spearhead on the creation of Darwinian evolutionary theory not strictly within the vague limits of Darwinian framework. This book gives us hints on her progress to moving closer to understanding the origin and evolution of eucaryotic mitosis and meiosis mechanisms.

In the book, Sagan and Margulis outline their major objections with neo-darwinian orthodoxy: the notion of mutation and its inherent implications, and argue that its current role in theory is misguided and overemphasized. They argue, rightfully so, the concepts of symbiogenesis and Gaia give much better traction to explaining change from a procaryotic world to the current world of the living than the doctrines of neo-darwinian selection via mutation.

Margulis and Sagan give a interesting account, and more importantly, several detailed examples of symbiosis, where the genome has clearly changed. Whether or not one is familar with Margulis's work, the accounts are enlightening, although I wouldn't recommend this book as an introduction to Margulis's symbiosis and Gaia metaphors, it gives enough to wet the appetite for more. I would recommend Microcosmos as better introductory book to get a better glimpse of the scope and revolutionary nature of Margulis's ideas. If one is interested in other details, her other books, such as the Symbiotic Planet are worth reading.

Clearly the most important part of the book, besides a few more of her and Dorion's insights into Gaia, is the report on her latest publishable material on evidence of the steps from procaryotic to eucaryotic organisms. She concentrates more on her evidence for the first major symbiotic pairing (amitochondriates) which eventually leads to the mitosis and meiosis mechanisms. Her detailing of karyomastigont and akaryomastigont mechanisms and their relations, gives one a better understanding of some of the major steps that most likely occurred from the transition from gross bacterial genetic mechanisms (e.g., plasmids, bacteriophages, and conjugation) to the full blown eucaryotic mitosis and meiosis mechanisms. Obviously, despite their compelling evidence, there looks to be a great deal of work to done to fill in gaps between the connected dots. But Margulis and Sagan provide an entertaining and informative overview on some of the issues entailed in determining the details.

The book is a tantalizing look at the edge of science, for if one is informed, one can see some interesting signposts ahead. The only problem I have with the book is once you start looking beyond the edge, you realize indeed Margulis has only a few explorers with her, and they haven't gotten very far. But that's the nature of science, isn't it.