A Theory of International Relations,"" M. Aron subtitles this monumental work. A clearer description is to be found in his brief foreword: ""My goal is to comprehend the implicit logic of relations among politically organized collectivities."" First published in French four years ago, Peace And War has been in no sense dated by subsequent developments. The broadcast possible view of the subject is taken, from four conceptual levels: ""theory, sociology, history, and praxiology."" Yet the focus is constantly upon the most immediate problems of the present and future. While the thinking and style reflect a most rigorous scholastic discipline, and the scope--together with such formal terminology as ""antinomies of diplomatic-strategic conduct""-- is forbidding, this volume deserves as wide an audience as possible. In his introduction, M. Aron notes that ""troubled times encourage meditation,"" that periods of intense disturbance bequeathed Plato, Aristotle, Hobbes, Locke, Montesquieu, and Rousseau, but that our own age has so far produced no comparable work. If there is anyone whose efforts might someday prove otherwise, it is Raymond Aron himself. Certainly he is one of the foremost political theorists of the 20th century.