The study of modern international relations is carried on, essentially, by two main types of scholars: diplomatic historians, and political scientists. There may be other types, like economists and sociologists, who recognize and take account of the importance of international politics in their own fields of study; but foreign affairs, and the processes that take place within the global system of relations, are not of central concern to them. By contrast, diplomatic historians (by which is meant here, not merely those who research into the rather narrow past actions of diplomats alone, but also those interested in the history of foreign policy and_what has affected it) would simply not exist if there was no perception and acceptance of international relations as a field of study; and this would be equally true of that well-defined sub-division of political science which has as its essential concern the analysis of relations between nation-states and of other ‘actors’ in the world system.

One of the main fields of historical research for the period between the two world wars has been the role of National Socialist Germany in world politics and the character of the British policy of appeasement. A difference of opinion as to the roots and aims of German and British policies in the 1930s continues to exist as a result of disparate interpretations of the decisive factors of these policies. The extent to which such factors as security interests at home and abroad, problems of trade, domestic and foreign policy, economic conditions and social change influence the policy-making process, as well as the impact these elements have on the capability or incapability for reform of the sociopolitical system, remains controversial.

The historical interpretations of British diplomacy during the 1930s are difficult to separate from those interpretations that explain the occurrence of the Second World War. Historians often link them by relating the British policy of appeasement to the outbreak of the war. British policy becomes a “permissive” cause of World War II by allowing Hitler to rearm Germany, consolidate western German frontiers, and expand towards the east. First, the British failed to prevent Hitler from occupying the Rhineland in March, 1936, and then merely protested the German annexation of Austria two years later. Within six months after the Anschluss Prime Minister Chamberlain accepted the cessation of the Sudetenland to Germany at Munich. Finally, after Hitler conquered the remainder of Czechoslovakia in the spring of 1939, the British guaranteed the territorial integrity of Poland. When Hitler attacked Poland in September, 1939, the British government, with the French as allies, came to Poland's defence. The British decision to honour this commitment belatedly but irrevocably reversed their earlier appeasement policy, which was to concede Hitler's territorial demands in an attempt to reach a peaceful European settlement with Germany.

On April 30, 1937 Sir Nevile Henderson arrived in Berlin and assumed charge of the British Embassy as His Majesty's Ambassador Extraordinary and Plenipotentiary. There appeared to be nothing unusual about the appointment which seemed on the surface to reflect the new more active attempts to approach the leaders of the Third Reich by Neville Chamberlain who knew that he would shortly become Prime Minister. What was unusual about the choice was the fact it was made by Sir Robert Vansittart, then Permanent Undersecretary at the Foreign Office and approved by Foreign Secretary Anthony Eden. Both men soon regretted the grave decision and Vansittart, as if to try to rectify his error, spent an enormous amount of energy during the next two and a Jialf years severely critizing Henderson's recommendations, evaluations and actions.

It is now twenty years since Richard Snyder and two associates published a monograph presenting their “framework” for studying international relations as foreign policy decision-making. The basic assumptions of this approach have become an indispensable part of the study of international relations. No-one would now think of ignoring the important processes by which groups of leaders formulate and choose among policy alternatives. Yet the approach itself has been relegated to subsections of surveys of the field, or dismissive footnotes. Although James Rosenau's influential anthology, International Relations and Foreign Policy, still retains three “decision-making” selections in its most recent edition, Rosenau himself pronounced a respectful epitaph for this approach some years ago. Glenn Paige's initial, massive study of the United States' intervention in Korea has had no successors.