At least as old as the alleged ʺinstinct of aggression,” according to Robert Ardrey, is the “instinct of territory.” The “instinct of territory”ʺ is defined by Ardrey as “an inherent drive to gain and defend an exclusive territory.” And, according to him, in defense of territory ʺthe instinct of aggressionʺ plays a major role. It is this viewpoint that Mr. Ardrey develops in his book The Territorial Imperative, published in 1966, and significantly subtitled A Personal Inquiry into the Animal Origins of Property and Nations. Man, Ardrey argues, has an innate compulsion to gain and defend territory, preserve, or property. And since the ʺsense of trespassʺ is so evident in the intruder, he wonders whether ʺthere does not exist, more profound than simple learning, some universal recognition of territorial rights.ʺ His personal inquiry leads him to the conclusion that such a profound recognition does exist, and that the territorial nature of man is genetic and ineradicable. It is Ardrey’ʹs thesis that man is as much a territorial animal as is a mockingbird. We defend the title to our land, the sovereignty of our country, in response to drives no different, no less ineradicable, than those that motivate other animals. The innumerable territorial expressions of man are simply human responses to an imperative lying with equal force on mockingbirds and men. And if this is so, says Ardrey, we must begin to think of a radical revision of our human nature. In fact, says he, so almighty a force is this territorial drive that in power it exceeds even the sexual drive. ʺHow many men have you known in your lifetime,ʺ asks Ardrey, ʺwho died for their country? And how many for a woman?ʺ It is a rough test, he admits, but it is clearly to him one that clinches the argument. It is the kind of logic that characterizes most of Ardrey’ʹs arguments. A part of our evolutionary nature, and fixed in our genetic endowment because of its survival value, Ardrey tells us, the territorial imperative is no less essential to the continuing existence of contemporary humans than it was to our early protohuman ancestors millions of years ago.