Geoffrey Gorer, for example, in his "Encounter" review of "The Territorial Imperative", writes: "Almost without question, Robert Ardrey is today the most influential writer in English dealing with the innate or instinctive attributes of human nature, and the most skilled populariser of the findings of paleo-anthropologists, ethologists, and biological experimenters." Ralph Graves claims "[Ardrey] today can claim major credit for having introduced the public to the new field of ethology, the study of animal behavior and its relationship to man." Commenting upon Ardrey's legacy on the occasion of his death, the South African anthropologist Dr. Phillip Tobias stated, "He has made an incalculable contribution to the science of human evolution. Thousands of people around the world, especially in the United States, were made aware of the fascination and the importance of studies on man's place in nature [through his writing]." The work influenced several notable figures. Stanley Kubrick cited Ardrey as an inspiration for his films "" (1968) and "A Clockwork Orange" (1971). The strategic analyst Andrew Marshall and U.S. Secretary of Defense James Schlesinger are known to have discussed "The Territorial Imperative" in connection to military-strategic thinking. Ardrey went on to publish two more books on human origins and the nature of man, "The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder" (1970) and "The Hunting Hypothesis: A Personal Conclusion Concerning the Evolutionary Nature of Man" (1976). He continued to publish influential works in the field of anthropology until his death in 1980. His theories are still widely discussed today.