W. D. Hamilton is one of the most influential biologists of the 20th century and is widely regarded as the most important theoretical innovator in the evolutionary study of behavior since Darwin. He is known throughout the world for his seminal work on social evolution (kin selection), sex ratio evolution and, more recently, for work on the involvement of parasites in sexual selection and on the evolutionary maintenance of sexuality. A Fellow of the Royal Society and a Foreign Honorary Member of the American Academy of Arts and Sciences, Hamilton is a Royal Society Research Professor in ...