Oxford zoologist Dawkins (The Selfish Gene, The Extended Phenotype) trumpets his thesis in his subtitle - almost guarantee enough that his book will stir controversy. Simply put, he has responded head-on to the argument-by-design most notably made by the 18th century theologian William Paley that the universe, like a watch in its complexity, needed, in effect, a watchmaker to design it. Hewing to Darwin's fundamental (his opponents might say fundamentalist) message, Dawkins sums up: "The theory of evolution by cumulative natural selection is the only theory we know of that is in principle capable of explaining the evolution of organized complexity."