We live with technology all around us, and we ignore it most of the time, unless it goes wrong. Most of the time, our gadgets go fairly close to right, and we don't have to think much about tending them, and we almost never think about how they are tending, and changing, us. Technologies created by people create different sorts of people. In _Our Own Devices: The Past and Future of Body Technology_ (Knopf), Edward Tenner has considered simple technologies, some so simple and ungadgety that we might not even think of them as technologies: bottle feeding of infants, footwear, chairs, keyboards, eyeglasses and helmets. His book is full of fun; Tenner has a host of obscure yet relevant facts that he has obvious pleasure in presenting. He writes, "This book is about the changes we have made in ourselves: how everyday things affect how we use our bodies." He has examples drawn from many disciplines in addition to the main ones, like the importance of styles of lacing of shoes or the effect of Taiwanese bowlers taking advantage of light bowling balls with lots of spin on them. There is a huge range of information within these pages.

One of the themes of the book is that the technique of use is an essential complement to the technology involved. Baby bottles, for instance, involve a technique that must be successfully learned by mother and infant. They also allow fathers a nurturing role denied by nature. Tenner does not get into polemics about the bottle versus nursing controversy (nor does he do so for any of the controversial technologies he explores). We are physically affected by our technologies. There are millions of people who live literally on the Earth, doing without shoes; of course we evolved to get around without shoes originally. There is a movement to promote barefoot hiking, but there is always a self-fulfilling problem to overcome: shoes cause our feet to be so sensitive and vulnerable that we need shoes to protect them. In Japan, many grow up wearing _geta_ (two-piece clogs), which means that their gaits are measurably different from those who wear, say, ordinary sandals, and may be the reason Japan has very few world-class runners. It was in 1853 that an inventor set up a chair with movable parts and a system of springs that would allow rocking, although the chair rested on a pedestal supported by casters. The chair was no longer static; "This was the beginning of a new technique of sitting." Extensive studies have been done in the water to show exactly what position a body in complete rest takes (although previous evaluation of sleeping positions gave the same information), with chairs engineered to ensure that position. Piano innards have changed because of insistence of composers, especially Beethoven, on more complicated and louder performances, but although there have been improvements in the keyboard itself, no superstar has promoted them and none caught on.

The examples come thick and fast throughout the book's chapters. The technologies of writing and printing and the technique of reading have actually increased myopia in literate societies, though the explanations of the physiology behind the change are not yet satisfactory. Eyeglasses that correct the myopia may cause children's eyes to grow differently, increasing the myopia. The hard helmet of football changed the way the game is played; coaches used to instruct players to wrap their arms around the ball carrier to bring him down, but the helmet made them into human battering rams. The fans' appetite for aggressive and violent plays increased. People who sit in chairs that have a backrest suffer from weakening of the back muscles so that they more acutely need a backrest: "The chair is a machine for producing dependency on itself." Again and again, Tenner's surprising examples show that technology is often quite wonderful, and of course indispensable, but we only understand what it does to us after close examination of its effects, and the effects themselves often could never have been anticipated.

This book deserves a 5-Star rating for the depth of its research, the overall quality of descriptive analysis, and the scope of its coverage. It is full of well-documented examples of technological unintended consequences.

It falls to a 3-Star rating for its failure to explain why these things happen, and for its dry, flat tone. I'm fairly sure this was written as a popular book on the subject, and not a text book, and as such we expect a different kind of writing. (College students are forced to read any number of numb, incomprehensible texts.) Other popular accounts of technical issues manage to hew to the science and engineering line with livelier writing. ("To Engineer is Human" is a good example.) "Why Things Bite Back" is clearly written, it just isn't a page turner, and lacks the sense of "I was there" that fosters a close relationship between the reader and the book.

The book failed to touch on other examples of unintended consequences. In fairness to Tenner, he never pretends to cover non-technological issues. The examples and impact of the law of unintended consequences in the social sciences, law, and government is possibly even greater than technological issues. Just as an example, think of the unintended consequences of the U.S. income tax laws. Tens (or hundreds) of thousands of professionals are paid billions of dollars a year to help citizens negotiate what started as a method of financing government. These social issues are at least as interesting as the technology issues. Maybe Tenner needs to write a second book.

Recommended, but not a good book for reading at the beach.

Boy, we humans make a mess of things, don't we? Our solutions to problems end up causing other problems. We can never get ahead of the curve. So, what's the point? Why do we bother inventing things? If we stopped right now, and lived like its 2002 forever, we will be in better shape, and live quieter, more stress-free, and even safer, lives. That is NOT what Tenner advocates in his book. But it is a conclusion one could reach when you read the litany of unintended consequences he provides.

Drawing on a rich variety of sources, Tenner shows quite clearly how and why we have unintended consequences. Once you read this book, you will find yourself thinking about many of the technological fixes in your life and wondering what unintended consequences they begat.

The next step - and maybe this can be Tenner's next book - is ask, what can we do about this situation? We cannot and should not stop innovation or problem-solving. But maybe we can do two things. One, explore how feedback loops can be enhanced, especially now that we are living in a digital world. It sounds silly when you read that someday, your refrigerator will order milk from a grocery store when it "senses" you are low on milk, but the faster and more efficient the feedback loops, the better we can be at forecasting danger ahead. Secondly, when a new solution or invention comes to fruition, look back for a moment, not ahead. Something is always lost when a new tool comes into human hands. Maybe the old tool had positive attributes we should try to keep. For a great example of this, read the little essay on railroads in George Kennan's Around the Cragged Hill. As he describes it, at the very point in history that the railroads had created a magnificent system, uniting the country while allowing it to spread, maximizing speed and safety, the car was invented. And the railroads withered. A sad story, the way he tells it. And while Kennan may be a little too romantic when it comes to 19th century rails, I am sure that there are many things about the rails that we have lost, now that we drive or fly.

I always appreciate a book that makes me think. This one does and is recommended.

This book is a well researched and enjoyable examination of some of the most perplexing outcomes of technological innovation. A well intentioned intervention that leads to unforeseen negative consequences is what Tenner calls a "revenge effect", and it seems that our modern world is full of them. An airline concerned with safety may require that all infant passengers have their own seat rather than travelling on the lap of an adult. However, since the seat will cost money, many families choose to travel by car which is more dangerous than air travel, and so more injuries and deaths result. Thus, the airlines' safety intervention has resulted in the revenge effect of a net increase in passenger injury and death.

Tenner claims, that the answer to many of these technological revenge riddles involves a deintensification of our technologies, and a better understanding of the greater system in which technological innovation takes place. Every new release of our technological products purports to be better, faster and stronger than the last, but hitting the problem harder with a more intense version of the same technology is not sustainable. Often this "improvement" race succeeds only in increasing the number and severity of revenge effects. Even in computing where advances have been exponential there is no hard evidence of anything more than a minimal increase in the efficiency of the average computer user. Better system understanding, coupled with technological deintensification will allow a more subtle, lasting, and better integrated solution to many problems.