" He who admits, on general grounds, that the structure and habits of all animals have been gradually evolved will look at the whole subject of Expression in a new and interesting light." -Charles Darwin Biografía del autor Charles Darwin, a Victorian scientist and naturalist, has become one of the most famous figures of science to date. Born in 1809 to an upper-middle-class medical family, he was destined for a career in either medicine or the Anglican Church. However, he never completed his medical education and his future changed entirely in 1831 when he joined HMS Beagle as a self-financing, independent naturalist. On returning to England in 1836 he began to write up his theories and observations which culminated in a series of books, most famously On the Origin of Species by Means of Natural Selection in 1859, where he challenged and contradicted contemporary biological and religious beliefs with two decades worth of scientific investigation and theory. Darwin's theory of natural selection is now the most widely accepted scientific model of how species evolve. He died in 1882 and was buried in Westminster Abbey.Sharon Messenger received her PhD in social history from the University of Liverpool. She is a Senior Research Assistant at the Wellcome Trust Centre for the History of Medicine at University College London. With Michael Neve, she co-edited Darwin's Autobiographies (2002), also for Penguin Classics. She was an assistant editor on the Oxford Dictionary of Scientific Quotations (2005). Currently, she serves as a research assistant for the Livingstone Online correspondence project.Joe Cain is Senior Lecturer in History and Philosophy of Biology at University College London (UCL). His expertise is in the history of evolutionary studies in the nineteenth and twentieth centuries, Darwin and historical memory. He is also director of the "Voices" oral history project at UCL, and an expert on the Rhinogradentia, a spectacular group of mammals. His recent books include Descended from Darwin (2008) with Michael Ruse, Sewell Wright Taught Me (2007) and Exploring the Borderlands: Documents of the Committee on Common Problems of Genetics, Paleontology, and Systematics, 1943-1944 (2004).