This book is intended as a primer for generalizing on a case-comparison basis about diplomatic statecraft, including resources and techniques available to states to attain their objectives. Twenty years in the making, it employs an inductive method in which small samples of cases occurring at different times and between different states are studied to track and understand specific variable diplomatic behavior. Its concern with empirically-grounded generalization, in which hypotheses are formulated and tested by case similarities and differences, is a new approach to diplomatic analysis. Diplomacy, though central to international relations study and practice, has generally been studied normatively rather than theoretically, in contrast to other international relations topics. Students of diplomacy, emphasizing statecraft's complexity, have generally shied away from theory, while theory-minded international relations analysts have neglected statecraft and highlighted military capabilities and positional rivalries as determiners of state behavior. This book instead builds diplomatic theory by investigating variation in case experience, especially in the diplomatic choices made by states. It shows that theorizing is enhanced by a diplomatic point of view and by distinguishing diplomatic behavior as cause and as effect.