Dian Fossey was an American zoologist, primatologist, and anthropologist who undertook an extensive study of mountain gorilla groups over a period of 18 years. She studied them daily in the mountain forests of Rwanda, initially encouraged to work there by anthropologist Louis Leakey. Her 1983 book, Gorillas in the Mist, combines her scientific study of the gorillas at Karisoke Research Center with her own personal story. It was adapted into a 1988 film of the same name. Fossey was murdered in 1985. Called one of the foremost primatologists in the world while she was alive, Fossey, along with Jane Goodall and Birutė Galdikas, were the so-called Trimates, a group of three prominent researchers on primates (Fossey on gorillas; Goodall on common chimpanzees; and Galdikas on orangutans) sent by Leakey to study great apes in their natural environments.