After years of intense specialization in historical studies —in the history of ideas, of science, of historiography; in economic history, diplomatic history, administrative history, social history, legal history, world history, which last is fast becoming another specialism—there is perhaps no subject of historical enquiry that would not benefit from an attempt to amalgamate the results of all these disciplines. This is certainly true of international relations. The valuable labours of diplomatic historians have done no more than erect a scaffolding of established facts. In the work of understanding and explaining those facts we have not made much progress since von Ranke and Albert Sorel. Von Ranke's famous essay in interpretation, ‘The Great Powers’, was written more than 125 years ago, before the rise of specialist studies. For this reason, as well as on account of the preoccupation of his generation with national mission and divine intention in a universal scheme, it necessarily fell back on a mystical conception of the society of states, on a spiritual conception of the role of the individual state—on what must now be regarded as general history of the worst kind.