This work is a classic and will surely be required reading for doctoral qualifying exams and graduate-level international relations theory courses... Essential. Choice ...an intriguing book about an important, if slightly baffling, episode in the intellectual history of International Relations... -- Ian Hall International Affairs ...a text that will be indispensable for the training of graduate students in IR and in diplomatic history broadly defined. -- Volker Berghahn H-Diplo Roundtable