My research and writing have developed largely at the intersection of my original scholarly interest in the European-American relationship with a concern about the impact of war that derived from teaching during America's Vietnam intervention. The traumas of the 1960's led many of us to reassess American ties with the rest of the world and, as it happened, inspired some historians to investigate a largely neglected question: to what extent international conflict transforms the participating nations. Out of this inspiration grew an edited volume in which I attempted to deal comparatively with the effects of the world wars and the Cold War on our history. During the same period I examined American relations with Germany in an earlier post-war era, publishing a book which focused on the United States' role in the Rhineland occupation, 1918-1923. In addition I became intrigued with questions of theory as they impinge on foreign relations, and at the end of the 1970s Spencer Olin and I found our perspectives sufficiently similar to collaborate on a study designed to show how a person's life situation and values influence theoretical notions in writing the history of human conflict.