The Huxley family was a distinguished British family of biologists and writers. Thomas Huxley (1825–1895) is best known for his support of Darwin's theory of evolution, without which acceptance of the theory might have been long delayed. Most of his own contributions to paleontology and zoology (especially taxonomy), botany, geology, and anthropology were related to this. He also coined the word "agnostic." His son Leonard Huxley (1860–1933), a distinguished man of literature, wrote The Life and Letters of Thomas Henry Huxley (1900). Of his children, three earned fame, Julian Sorell Huxley (1887–1975) is best known as a biologist and ecologist. His early interests were in development and growth, genetics and embryology. Later he made important studies of bird behavior, studied evolution, and wrote many popular scientific books. He served as secretary of the Zoological Society of London (1935–1948) and as director general of the United Nations Educational, scientific, and Cultural Organization (UNESCO) (1946–1948). His books include The Individual and the Animal Kingdom (1911) and Evolutionary Ethics (1943). Aldous Leonard Huxley (1894–1963) was one of the 20th century's foremost novelists. Andrew Fielding Huxley (1917–2012) shared the 1963 Nobel Prize in Physiology and Medicine with Alan L. Hodgkin and John Eccles for his work with Hodgkin on the chemical basis of nerve impulse transmission.