Robert Ardrey was an American playwright, screenwriter and science writer perhaps best known for The Territorial Imperative (1966). After a Broadway and Hollywood career, he returned to his academic training in anthropology and the behavioral sciences in the 1950s.

The Territorial Imperative: A Personal Inquiry Into the Animal Origins of Property and Nations is a 1966 nonfiction book by American writer Robert Ardrey. It describes the evolutionarily determined instinct among humans toward territoriality and the implications of this territoriality in human meta-phenomena such as property ownership and nation building. The Territorial Imperative was an immediate success and remains a widely influential work of popular science. It extended Ardrey's groundbreaking anthropological work, contributed to the development of the science of ethology, and encouraged an increasing public interest in human origins.