The theory of evolution really does explain everything in biology. The phenomena that Darwin understood in broad brush strokes can now be accounted for in the precise language of DNA. And though biological systems have attained extraordinary levels of complexity over the passage of time, no serious biologist doubts that evolutionary explanations exist or will be found for every jot and tittle in the grand script.

To biologists and others, it is a source of amazement and embarrassment that many Americans repudiate Darwin’s theory and that some even espouse counter­theories like creationism or intelligent design. How can such willful ignorance thrive in today’s seas of knowledge? In the hope of diminishing such obscurantism, the prolific English biology writer Richard Dawkins has devoted his latest book to demonstrating the explanatory power of evolutionary ideas while hammering the creationists at every turn.

Dawkins invites the reader to share the frustration of an imaginary history teacher, some of whose students refuse to accept that the Roman Empire ever existed, or that Latin is the mother tongue from which the Romance languages evolved. Instead of concentrating on how Western culture emerged from the institutions of the Roman state, the teacher must spend time combating a school board that insists he give equal time to their alternative view that French has been spoken from time immemorial and that Caesar never came or saw or conquered. This is exactly analogous to the plight of the biology teacher trying to acquaint students with the richness of modern biology in states where fundamentalist opponents of evolution hold sway.

Dawkins has a nice sense of irony, deployed without mercy on the opponents of evolution. If the creationists think the earth is less than 10,000 years old, rather than 4.6 billion, he asks, shouldn’t they assume, by the same measure, that North America is less than 10 yards wide? The book is even more enjoyable when Dawkins forgets the creationists and launches into evolutionary explanations, whether of the hippopotamus’s long-lost cousin the whale, or of the long-tongued moth that Darwin predicted must exist to pollinate a Madagascan orchid with a nectary 11 inches in length. He gives striking examples of “unintelligent design,” forced on evolution because it cannot ever start from scratch but must develop new structures from older ones.