The names themselves are weird: Yohoia, Opabinia, Hallucigenia. . .and more. They are among the weird and wonderful creatures buried in the Burgess Shale, a minuscule quarry ""little taller than a man, and not so long as a city block"" in British Columbia. They were the mother lode for Smithsonian Director C.D. Walcott, an indefatigable geologist/administrator who discovered the trove in 1909, and, true to the spirit of the times, ""shoehorned"" all these Cambrian marine specimens (over 500 million years ago) into a few latter-day phyla. And there's the rub, cries Gould, lecturing with a vengeance to eradicate what he sees as the two chief myths of evolution: the ladder of progress (from primitive and simple to glorious US) and the cone of diversity (from restricted and simple to more and better). The Burgess Shale is the crowning demonstration of a Christmas tree analogy: wonderfully rich and complex forms spread across the bottom branches, in time tapering to a few stereotyped branches at the top. Paleontologists Harry Whittington, Derek Briggs, and Simon Conway Morris re-dissected Walcott's fossils, revealing three-dimensional details of forms the likes of which have never been seen--like five-eyed, vacuum-cleaner nozzled Opabinia or bulbous-headed, spined and tentacled Hallucigenia Moreover, the explosive abundance of Burgess has now been repeated at other early sites. For Gould this means that life is maximal at the start, exploding in different shapes and styles that are subjected to the contingencies of history. Unpredictable events can destroy nearly all life, creating opportunities for the remainders. Replay the tape of history and you might end up with predacious birds, not mammals or men. Heady stuff this: Gould demands that readers learn anatomy, and he likes laboring points. But Gould fans will cheer this latest exhortation against purposive creation in favor of a universe ""offering us maximum freedom to thrive, or to fail, in our own chosen way.