This book offers a stimulating challenge to medicine and a thoughtful discussion of how (Darwin) evolution theory applies to us. Mr. Nesse and Mr. Williams provide a careful survey about how evolutionary factors can shape and affect human health - the causes and effects are being discussed in a plain-language manner. Have you ever thought about how the sneezing, the fever, and the coughing are all front-line responses of our immune system? Why do you think the once-eradicated TB come back with a more potent strand? The book provides a refreshing yet convincing view that bacterial resistance to antibiotics is an everlasting arm race.

This is a very readable book and an excellent introduction to a subject that has hitherto been sorely neglected. The main argument presented by Nesse and Williams is that disease must be understood from the perspective of evolutionary biology.

The authors begin by asking, "Why, in a body of such exquisite design, are there a thousand flaws and frailties that make us vulnerable to disease?" Through evidence and insights from evolutionary biology, the authors carefully give a detailed answer to this question, which might be summed up thus: The mechanism of evolution fits our bodies for reproduction, not for optimum health. Furthermore the mechanism is imperfect and subject to mutation. Additionally we are in competition with other organisms, e.g, viruses, bacteria, etc., that work toward their fitness, sometimes at our expensive (the parasite-prey "arms race"). Noteworthy is the idea that natural selection cares little for the maintenance of the organism after the age of reproduction, and that sexual reproduction actually fosters mechanisms that increase the fitness of youth while neglecting the aged, leading to the phenomena of senescence and death.

Seeing disease from the viewpoint of evolution, the authors argue, helps us to understand disease and the mechanisms involved, which in turn can help us to fight disease. Allergy, for example, is a disease characterized by an over active immune system. Copious amounts of histamine are produced to fight off a few molecules of pollen. Why? The authors make the point that our immune systems operate on the principle that better an overreaction to something harmless than an under reaction to a real threat. It's like jumping at the sight of a piece of rope lying on the ground. It's not a snake, but better this little harmless error than being too slow to get back from the real thing.

Some other interesting ideas: Fever has a purpose. It raises body temperature enough to interfere with the chemistry of some pathogens, thereby killing them. If we take medicines that reduce fever, are we prolonging our illness? In some cases, the authors answer, yes. If we take medicines that suppress coughs and sneezing can that also prolong our illness? Again the answer is in some cases, yes. The point is that in treating the symptoms of disease we need to make a distinction between which are defensive mechanism of our bodies and which are not. Some pathogens, for example, make us sneeze or cause diarrhea in order to better spread themselves to the next victim. The rabies virus makes a dog bite other animals in order to spread itself. But our bodies cause us to cough and sneeze primarily to expel pathogens.

The authors see some of our health problems as the result of genetic "quirks," or evolutionary hangovers. Dyslexia as an example. In the Environment of Evolutionary Adaptation back in the Stone Age, dyslexia was no problem because there were no books to read. Indeed, it might be that the dyslexic approach to some perception problems, is better than the "normal" one, allowing a quicker, better understanding of the objects being viewed. Other genetic quirks include our predisposition to eat too much fat when available because in the EEA there was precious little fat to be had so it made sense to eat as much as possible when it was available. Something similar can be said of alcohol. Before agriculture, and especially before the process of distillation, a predisposition to alcoholism was no danger because there was very little alcohol to be had. These "quirks" are examples of disease caused by "novel environments," much of the modern world being a novel environment to our Stone Age bodies.

Nesse and Williams show that the modern environment, which requires a lot of close work from all of us, especially the reading of books, is the cause of the epidemic of myopia that modern humans experience. I would like to add that it is possible that myopia under some conditions could be adaptive. In the rainforest it would probably be better to see well close at hand than far away (the opposite of what would be valuable on the savannah). Also those people who concentrated on things small and up close might well identify and process food sources overlooked by others.

While this is an excellent book, gracefully written and full of valuable information and insight, it is now a little dated (copyright 1994), and some of the ideas need reworking in light of recent discoveries. For example, while the authors discuss the ill effects of too much fat and sugar in our diets, they say nothing about the carbohydrate intolerance that leads to obesity. This too can be seen as an evolutionary quirk since there were no cultivated fields of amber grain in the prehistory, and the grains that were available were small and required a lot of hand processing so that it was very difficult to overindulge. Consequently there was no need for natural selection to evolve a protection against eating too much. Also their discussion of heart disease and how it is the result of genetic factors and faulty diet fails to mention the idea that heart disease might be caused by a bacteria. (See for example, Plague Time: How Stealth Infections Cause Cancers, Heart Disease, and other Deadly Ailments (2000) by Paul W. Ewald.)

All things considered, though, this is a classic of evolutionary literature, nicely presented to a nonspecialist, but educated public. Now if we can only get the doctors to read it!

Slightly modifying an oft-quoted line by the famous biologist Dobzhansky, Nesse and Williams conclude, "After all, nothing in medicine makes sense except in the light of evolution." In this lucidly written book, the authors make this assertion throughout. They lay out principles for interpreting aspects of human health from an evolutionary perspective. For example, some of the body's responses can be viewed as adaptive defenses (e.g. fever), others the products of novel environments (e.g. Sudden Infant Death Syndrome, or SIDS). The authors raise intriguing examples, from adaptive withholding of the body's iron stores to pregnancy sickness, that put flesh on the bones of these principles. This book does a fine job of overviewing the ways in which an evolutionary perspective can contribute to a richer understanding of medicine than the more proximate (e.g. what are the chemical and genetic bases to schizophrenia?) focus alone can provide. For this reason, it may long be seen as a seminal contribution.