An influential nineteenth-century naturalist and explorer, Wallace is credited with helping to formulate the principles of biological evolution and natural selection. Wallace was born in 1823 in Monmouthshire, England, the eighth of nine children of a poor family in England. His formal education ended when he left school at the age of 14, but he was a voracious reader who readily absorbed a wide variety of subjects. In 1837, Wallace moved to London to become apprenticed to his brother, a surveyor. His interest in botany and biology began during these years, and he began to read widely in the natural sciences. From 1844 to 1845, he was a master at the Collegiate School in Leicester, where he taught a variety of subjects.

Wallace's scientific career really began in 1847, when he convinced a fellow amateur botanist, Henry Walter Bates, to join him on an expedition to South America to collect objects of natural history...