Evolution is the most important idea in biology, with implications that go far beyond science. But despite more than a century's progress in understanding, there is still widespread confusion about what evolution is, how it works and why it is the only plausible mechanism that can account for the remarkable diversity of life on Earth. Now, for the first time in a book aimed at a general audience, one of the founding fathers of modern biology tells us what we know - and what we do not know - about evolution. In showing how evolution has gone from theory to fact, he explores various controversial fads and fallacies such as punctuated equilibrium, the selfish-gene theory and evolutionary psychology. He ends by looking at what we know about human evolution and how, in turn, this knowledge has affected the way in which we view ourselves and the world.