From the very days of the drafting of the Covenant of the League the problem of sanctions has been in the forefront of discussion of international organization and government. Even the warmest adherents of the League hope to see the day when its powers will be enhanced and methods provided for making its decisions effective. Its critics, on the other hand, have repeatedly pointed out its failure to solve the burning question of disarmament and to provide security. Among these critics is the author of the present volume, an English politician who has given years of thought to the problem of sanctions. In this imposing book he reviews the question historically and revives the oftmade suggestion for the creation of an international police force. He believes that this force should be composed of contingents from the various members of the League, and that its superiority over any national police force should be secured by giving it a monopoly of the most modern weapons of warfare. The idea is expounded in great detail and with some cogency, while in separate chapters the author examines the relation of the major Powers to such a projected organization. The book is based upon wide reading and a substantial body of knowledge, and will well repay the attention of all students.