Alfred Russel Wallace (1823-1913), co-discoverer of natural selection, was second only to Charles Darwin as the 19th century's most noted English naturalist. Yet his belief in spiritualism caused him to be ridiculed and dismissed by many. Though based upon very different formulations of natural selection, the Wallace/Darwin dispute as presented by Flannery shows a metaphysical clash of worldviews coextensive with modern evolutionary theory itself.