International relations analysts now use a wide range of ideas and techniques. Concepts and styles of reasoning clearly reflect work in economics, organizational behavior, social psychology, operations research and many other fields. Facts thought relevant are the facts customarily used in these other fields. Methods for relating facts to each other and to ideas are increasingly those of logic, statistics and mathematics. What are the implications of this diversity for foreign and defense policy? The only necessary implication is for the length and variety of the menu international relations analysts can offer the policy person. There is no necessary implication for how important or satisfying he will find the offerings.

Ever since Plato advocated his ideal of a philosopher-king, the intellectual has sought to guide the destinies of state. Sometimes he has been openly explicit in articulating advice, as with Machiavelli. More often, however, the intellectual has abjured so crass a role. Instead, he has sought to influence through private persuasion or has rendered counsel indirectly through scholarly essays. Only in China did the dichotomy between scholar and statesman disappear some two thousand years ago with emergence of a political system that monopolized bureaucratic control in the hands of the literati, that infinitesimally small proportion of the population that could master the classical adages which comprised the examinations for entrance into government. Elsewhere the sword proved to be mightier than the pen, at least in determining affairs of state.

Approaches to the study of international relations employ a wide variety of concepts and indicators. The interrelationships among these concepts often are specified in conceptual schemes, models, or theories. This supplementary issue of World Politics presents several approaches to international relations theory which utilize familiar concepts, such as decision-making, crisis, and interdependence, and also concepts (frequently borrowed from other disciplines) that are less familiar, e.g., entrepreneurial and consumer roles, free riders, and externalities. The diversity of approaches and the variety of models specified by the contributors led the co-editors to commission an index focusing on concepts and the variables used to tap the concepts (indicators) rather than a more traditional listing of names, places, and events.