Explores the life and scientific contributions of Alfred Russel Wallace, Victorian traveler, scientist, spiritualist, and co-discoverer with Charles Darwin of natural selection. This biography also examines his travels in the western and eastern tropics. It casts light on his work and the importance of his relationship with Charles Darwin.

In addition to his divergence from Darwin on two fundamental issues - sexual selection and the origin of the human mind - he pursued topics that most scientific figures of his day conspicuously avoided, including spiritualism, phrenology, mesmerism, environmentalism, and life on Mars. Although there may be disagreement about his conclusions, Wallace's intellectual investigations into the origins of life, consciousness, and the universe itself remain some of the most inspired scientific accomplishments in history. This authoritative biography casts new light on the life and work of Alfred Russel Wallace and the importance of his twenty-five-year relationship with Charles Darwin.