During his long career Alfred Russel Wallace wrote more than four hundred articles and reviews as well as more than twenty-five books and is best remembered for his biological and ethnological investigations. Like Charles Darwin, Thomas Huxley, and Joseph Dalton Hooker, Wallace sailed strange seas in pursuit of knowledge, which in his case took him to the Amazon and to the Malay Archipelago. Like them, he also undertook journeys over strange seas of thought, sharing with his contemporaries a belief in evolution, but unlike them his interests carried him from the exotic to the erratic, to a defense of spiritualism as an empirically authenticated practice. In the realm of reform he became an advocate for socialism as the cure for a culture wounded by capitalistic spoliation.

Wallace is credited with conceiving the idea of natural selection independently of Darwin and was evidently the first to commit a complete...