A folklorish giant

Alfred Russel Wallace, heroic naturalist, anthropologist, and evolutionary theorist, began his ninety years in a Welsh cottage as so unpromising a new-born that the family performed a make-do “half-baptism” until the vicar could do a proper one at Llanbadoc five weeks later, on 16 February 1823. He went through his life being the short half of great enterprises. He and Darwin discovered the mechanics of evolution neck-and-neck. He and Henry Walter Bates explored the Amazon together, but Bates’s Naturalist on the River Amazons remains the classic account. In the great foment of Victorian geology, etymology, and botany he was—until his last decade—looked down on as the lower-class boy from the Welsh hills who didn’t quite fit in with the gentlemen at the Royal Society.

Wallace was also accident prone. All in one day in the Brazilian jungle he infuriated a swarm of bees, lost his glasses, and...