Steven Jay Gould (1941-2002), the popular and prolific science writer and paleontologist, was adept at the encapsulating essay; his short pieces compiled into thematic volumes are very enjoyable. So I was not prepared for Wonderful Life, which focuses on a single topic for an entire book: the Burgess Shale, and the implications of the fossils found there.

When C.D. Walcott's wife's horse kicked a curious stone out of the snow, leading to discovery of the rich fossil beds of the Burgess Shale, it nearly tripled the number of examples of Cambrian life-forms. Even more important, because of the way the fossils were preserved—in successive mud-flows—we have fossils that show antennae, legs and other delicate features that heretofore had been lost in the fossilization process.

Gould tells how the contents of this trove have shaped our knowledge and theory of these early life-forms. The first part of Wonderful Life, in which he covers the finding and publication of the fossils, has the genuine Gould appeal; the feeling of being involved in a scientific discovery.

Gould uses the breadth of the Burgess fossils to illuminate evolution: "In conventional Darwinian theory, the organism proposes and the environment disposes... competition is the great regulator... Thus, diversity is self-regulating..." How, then, he asks, did we get the "Cambrian explosion", the unprecedented growth in types of complex organisms that "suddenly" appear at the opening of this geologic age?

He answers the question, in part, by exploring the theories of Harry Whittington, Simon Conway Morris and Derek Briggs. These Cambridge paleontologists responded to the wealth of possibilities opened by the finely-detailed Burgess fossils by proposing a new Phylum designation for each of the unique forms found in the shale. (An equivalent might be assigning star catalog designations to meteorites.)

Even more strangely to the science-reader's eye, Gould then diverts into a phenomenon he calls

Contingency... the control by immediate events over destiny, the kingdom lost for want of a horseshoe nail... The theme of contingency, so poorly understood by science, has long been a mainstay of literature...

Indeed, this theme gave the book its title—after quoting Ruth Rendell, Stephen King, Kurt Vonnegut and the movie Back to the Future, Gould nominates the Frank Capra movie It's a Wonderful Life as the holotype (perfect example) of contingency thinking. And the contingency he has set up as straw-man for his book to tackle? The (long-since outmoded) concept that "that evolution marches inexorably towards a pinnacle such as man".

The book is both enjoyable (particularly in the first part) and deeply disturbing, as it shows one of Gould's few flaws: his pursuit and popularization of ideas and theories that would serve to justify his own personal beliefs. Wonderful Life is a wonderful book—just not wonderful science.

"The true index of how unalike two animals are is how unalike they actually are!" is the crux of Richard Dawkins' critique of the book. "If only Stephen Gould could think as clearly as he writes!" Dawkins (author of The Selfish Gene) is a member with Daniel Dennett of a coterie of science philosophers who have long had disagreements with Gould's conclusions.