THE British Empire after 1919, Liddell Hart once observed, was the greatest example of strategical over-extension known to history. Like the Roman or Spanish empires in earlier centuries, the gap between the country's obligations and its capacity to carry them out had become alarmingly wide – too wide, in fact, to be ever closed. The blunt fact was that, by the third and fourth decades of the twentieth century, Britain was well into a process of decline, militarily, economically and geopolitically, vis-à-vis certain of the other Great Powers, who were soon o t usurp her predominance in various parts of the globe.1 To a large extent, the First World War and its consequences – the defeat of Germany and the seizure of its colonies, the Soviet revolution in Russia, the American retreat into isolationism – had suggested to the public mind that the British Empire was still as formidable as ever and thus was masked this process of decline until, by 1945, it had become clear to almost everyone. In the secret discussions and analyses of British statesmen and their advisers, however, the weaknesses within the system of home and imperial defence were all too apparent long before that date. To the ‘official mind’, the 1930s in particular was a decade of almost continuous anxiety as the ever more frequent international crises exposed the inadequacies of the armed services and affected the country's diplomacy. Because this topic relates directly to the discussion upon ‘appeasement’ and, indirectly, to the origin and course of the Second World War, it has always been one ofgreat interest to historians; but the restrictions upon the use of government records of the inter-war years made it impossible until a few years ago to know more than that which was related in the memoir literature and in the official war histories written in the post-1945 period. Now that the archives are open and new studies based upon their holdings are appearing in large numbers, it is possible to obtain a much more detailed picture of the workings of British defence policy during the “Twenty Years Crisis”. What follows, then, is an attempt to summarize the findings of a variety of such publications which have appeared over the course of the past two years.