The aim of this work, as stated by the author, is to set forth in scholarly fashion what he believes to be the central issue in national security policy- the choice between deterrence of and defense against military attack and the allocation of resources and the management of diplomatic declarations in the service of these two ends. Snyder points out that once upon a time the same weapons that served as deterrents against attack could also be used equally well to defend against the attack if it came. The long-range bomber, and the later nuclear weapons, changed this simple concept. This book shows how. It is, however, not for the layman and it is to be studied rather than perused. So complex have deterrent and defense problems become that the author presents these on occasion in what amounts to mathematical exercises. The picture that emerges is one of a gigantic chess game in which leaders on both sides must grapple with multiple choices which include such esoteric concepts as guessing what the other side might guess about you. An intricate, interesting presentation.