Kenyan physical anthropologist and paleontologist, son of Louis and Mary Leakey, responsible for extensive fossil finds of human ancestral forms in East Africa. His investigations suggested that relatively intelligent, tool-using ancestors of true man lived in eastern Africa as early as 3,000,000 years ago, or almost twice the time span of previous estimates. Leakey uncovered some 400 hominid fossils, making Koobi Fora the site of the richest and most varied assemblage of early human remains found to date in the world. Leakey proposed controversial interpretations of his fossil finds. In two books written with science writer Roger Lewin, "Origins" (1977) and "People of the Lake" (1978) Leakey said that about 3 million years ago three hominid forms coexisted with each other: Homo habilis Australopithecus africanus and Australopithecus boisei. Leakey contended that a relatively large-brained upright bipedal form of the species Homo lived in eastern Africa c 2.5-3.5 million years ago. He also wrote "The Making of Mankind" (1981).