Alfred Russel Wallace (1823 – 1913) was a British naturalist, explorer, geographer, anthropologist and biologist who wrote on both scientific and social issues. Independently developing a theory of evolution based on natural selection, he still encouraged Darwin to publish his own evolution theory. One of his best known works, Malay Archipelago, helped to create “biogeography,” the study of environmental impacts of human activity. Wallace’s Spiritualism was to influence his scientific thinking (as expressed in The World of Life, published in 1910), creating critical skepticism with the scientific establishment of his day.