In his AUTOBIOGRAPHY, written in 1876 but published posthumously, the great naturalist Charles Darwin reflects on those crucial events that resulted in his discovering the scientific theory of organic evolution by means of natural selection. He examines his five-year voyage on the HMS Beagle and subsequent preparation of a manuscript for his pivotal work, ON THE ORIGIN OF SPECIES (1859). Also included are many of Darwin's important letters, edited by his son, Francis. They reveal the freethinking geobiologist's thoughts on religious beliefs, scientific research, and the bitter controversy surrounding the far-reaching ramifications of evolutionary theory for life on Earth (including our own species). The reissue of this volume is a major contribution to the history and philosophy of evolutionary thought.