The Evolution Ringmaster RichardDawkinsThe Greatest Show on Earth: The Evidence for Evolution2009Simon and SchusterNew York, NY, USA470 pp. $30.00

Caravan, and Hippodrome, " a year later adding the moniker " The Greatest Show on Earth. " Ever the showman, Barnum was renowned for promoting hoaxes, the most celebrated of which was the Feejee Mermaid, a mummified specimen boasting the head and torso of a monkey and the rear end of a fish. Such a ridiculous creature, what Richard Dawkins would refer to as a " fishkey, " half fish and half monkey, is precisely what many creation-ists clamor for. " If monkeys descended from fish, " they say, " then show me an intermediate form! " In his latest book, The Greatest Show on Earth, Dawkins points out the absurdity of this expectation. First, modern species are not descended from other modern species. Rather, they share a common ancestor some time in the past. Second, there is no reason to think that this ancestor would be perfectly intermediate in form between its descendant species. With a flair for analogy and unique explanatory abilities, Dawkins confronts such creationist myths one by one. He is an entertainer but, unlike Bar-num, he sticks to the facts. Although Dawkins carefully dismantles the underpinnings of creationist thinking, he is in fact uncharacteristically restrained. This is not the unrelenting attack on religion that made his previous book, The God Delusion, controversial. Instead, inspired by the bicentennial of Darwin's birth, Dawkins harnesses the wonders of the natural world to lay out the evidence for evolution. For Dawkins, the marvels of biological diversity—from the origami-like folding of developing embryos to the seaweed-grazing marine iguanas of the Galapagos Islands—both ask and answer evolutionary questions. In so doing, Dawkins covers vast territory with crystal-clear scientific thinking and wonderful prose, the Dawkins hallmark. The book starts semantically: what is a theory? Although not the sexiest of entrées, this single word " theory " belies a central confusion about evolution, and so it must be done. In the 1980 presidential campaign, Ronald Reagan, when questioned about his views on evolution, responded " Well, it's a theory…it is a scientific theory only… " This lack of awareness (or political tap-dancing) highlights a key dichotomy in the usage of the term: the general public uses theory to mean speculation or conjecture, whereas scientists define it as a hypothesis confirmed by observation or experiment and accounting for the known facts. Unlike many of his previous books, which assume the fact of evolution, here Dawkins …