Eight years ago, Harper's Magazine editor Michael Pollan bought an old Connecticut dairy farm. He planted a garden and attempted to follow Thoreau's example: do not impose your will upon the wilderness, the woodchucks, or the weeds. That ethic did not, of course, work. But neither did pesticides or firebombing the woodchuck burrow. So Michael Pollan began to think about the troubled borders between nature and contemporary life. The result is a funny,...