Alfred Russel Wallace, the English naturalist and coformulator with Charles Darwin of the theory of natural selection, was born at Usk, Monmouthshire. He was largely self-educated, having left school at fourteen to serve as a surveyor's assistant with his brother. Like many of his contemporaries he acquired an early taste for the study of nature. But he also read widely and was influenced by the works of Alexander von Humboldt, Thomas Malthus, and Charles Lyell, as Darwin was. In 1844, while teaching school at Leicester, he met the naturalist H. W. Bates (1825–1892), who introduced him to scientific entomology. The two men later embarked on a collecting trip to the Amazon, where Wallace remained for four years examining the tropical flora and fauna.

In 1854, after a brief visit to England, Wallace set out by himself for the Malay Archipelago. He subsequently wrote an account...