There are 4 books in the Robert Ardrey's Nature of Man series series. The newest book is The Hunting Hypothesis which came out in 1976.

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The Territorial Imperative

By Robert Ardrey , Berdine Ardrey (illustrator) ,

Book cover of The Territorial Imperative
A territory is an area of space which an animal guards as its exclusive possession and which it will defend against all members of its kind. In this revolutionary book Robert Ardrey takes a concept familiar to every biologist, brings together for the first time a fair sampling of all…

4
The Hunting Hypothesis

The Hunting Hypothesis
Combines archaeological, anthropological, and historical evidence in an account of those characteristics that enabled man to survive and dominate