EDWARD O. WILSON, a professor at Harvard University who studies the behavior of ants and other

insects, has written a very personal book whose

overt purpose is to convince us of the value and importance of conservation. But actually it does much more. His broader thesis is that humans are irresistibly drawn to all forms of life -- a tendency that he calls biophilia. Much of Biophilia consists of absorbing personal anecdotes, fascinating descriptions of animal behavior and speculations about why humans behave the way they do. He describes the world of insects and strange experiences like that of walking through a tropical rain forest where, periodically one hears "a sharp crack like a rifle shot, folloed by a whoosh and a solid thump. Somewhere a large tree, weakened by age and rot and top heavy from layers of vines, has chosen that moment to fall and end decades or centuries of life."

As might be expected in a book that includes such an array of topics, there is some discontinuity. It is sometimes difficult to see what certain chapters have to do with conservation or with Wilson's broader thesis. But, despite these faults, Biophilia is an immensely readable book. Wilson is a master storyteller, skillful at evoking exotic scenes.

Wilson believes that behavior, like eye color and height, has a genetic basis -- a controversial hypothesis outlined in his earlier book, Sociobiology. His proposals, that traits like altruism and cultural attributes like incest taboos might be genetically based, were attacked by critics as being speculative at best. Compelling as the arguments for an evolutionary basis of behavior may sound, they are not in the category of scientific truth. Wilson is too good a scientist not to recognize this and, in fact, he tells us, "In the chaste idiom of scientific discourse, we are permitted to conclude only that the evidence is consistent with the proposal." Even so, Wilson does not attempt to defend his thesis of biophilia in anything like a scientifically credible way. But because he is such a good writer, it is easy to be drawn along by the arguments in Biophilia and lose sight of their limitations.

FOR EXAMPLE, according to Wilson, humans are

fascinated by serpents, holding them in "awe and

veneration." Moreover, he says, "The mind is

primed to react emotionally to the sight of snakes, not just to fear them but to be aroused and absorbed in their details, to weave stories about them." That is why serpents figure so prominently in mythology and religion, he says. Certainly, Wilson himself is fascinated by snakes. As a boy living in Florida and Alabama, he hunted snakes, hoping to find a "real serpent" -- a snake that was so enormous or unusual that it was beyond the bounds of the imagination. He prowled through swamps, grabbing snakes and eventually capturing nearly 40 species. But only when he had a terrifying encounter with a water moccasin -- his true serpent -- did he finally give up this dangerous persuit.

We are morbidly entranced by snakes, Wilson says, because when the human brain was evolving, "snakes mattered." We learned to fear snakes and that tendency was transmitted from generation to generation. The argument, as Wilson develops it, makes some sense and is, at the very least, provocative. But it is hardly conclusive.

Wilson also hypothesizes that humans evolved to prefer landscapes which resemble the savannas of Africa where we originated. For example, he says, we seek "open tree-studded land on prominences overlooking water." And we design landscapes so that they resemble savannas. One particularly striking instance of this is the Japanese gardens from the 9th through the 12th centuries with their carefully arranged trees, shrubs, streams and ponds. The Japanese, in fact, pruned their trees, "to resemble those of the tropical savanna in height and crown shape. The dimensions are so close as to make it seem that some unconscious force has been at work to turn Asiatic pines and other northern species into African acacias."

Our fascination with snakes and with savannas, Wilson argues, exemplifies our ties to other organisms -- ties tht we have hardly begun to fathom or truly appreciate. Because of this biophilia, he says, our very humanness itself is threatened by the precipitous extinctions that are now underway. We are losing about 1,000 species a year, mostly because we are destroying tropical forests. In a decade, according to Wilson, we will be losing more than 10,000 species a year, or more than a species an hour. We must reverse this process, he says, and recognize the depth of our ties to all life. "If no country pulls the trigger the worst thing that will probably happen -- in fact is already well underway -- is not energy depletion, economic collapse, conventional war, or even the expansion of totalitarian governments. As tragic as these catastrophes would be for us, they can be repaired within a few generations. The one process now going on that will take millions of years to corrrect is the loss of genetic and species diversity by the destruction of natural habitats. That is the folly our descendants are least likely to forgive us."

Although Wilson is ultimately not entirely convincing, he writes so well and his tales are so haunting that it almost does not matter. I would like to think that his argument for conservation will make a difference, but the fact that it probably will not does not diminish the charm of his book.