Wonderful Life: The Burgess Shale and the Nature of History is a 1989 book on the evolution of Cambrian fauna by Harvard paleontologist Stephen Jay Gould.

He based his argument on the extraordinarily well preserved fossils of the Burgess Shale, a rich fossil-bearing deposit in Canada's Rocky Mountains, dating 505 million years ago.

[5] Gould proposed that given a chance to "rewind the tape of life" and let it play again, we might find ourselves living in a world populated by descendants of Hallucigenia rather than Pikaia (the ancestor of all vertebrates, or at least a close relative thereof).

"[8] Gould earlier coined the term exaptation to describe fortuitously beneficial traits, which are adaptive but arise for reasons other than incremental natural selection.

"[15] Philosopher Michael Ruse wrote that, "Wonderful Life was the best book written by the late Stephen Jay Gould, paleontologist and popular science writer.

[17] Conway Morris' reconstruction was, "so peculiar, so hard to imagine as an efficiently working beast" Gould speculated that Hallucigenia might be "a complex appendage of a larger creature, still undiscovered.

"[18] It was later brought to light by paleontologists Lars Ramskold[19] and Hou Xianguang[20] that Conway Morris' reconstruction was inverted upside down, and likely belonged to the modern phylum Onychophora.