In recent years, the U.S.–Japan alliance has marked several anniversaries, including 40 years since the 1969 decision on the reversion of Okinawa. These occasions have provided crucial opportunities to reassess the continuing significance of U.S.–Japan security and diplomatic relations, prompting this investigation into major issues in negotiations between the two countries. This book is the first comprehensive and comparative analysis of the U.S. and Japanese foreign policy formulation and implementation processes from 1961 to 1978, which also explores the long-term strategic significance of the U.S. deterrence in East Asia. It is based on numerous declassified and previously unused U.S. and Japanese documents, oral histories, and the author’s interviews with former officials. The book traces the origins of contemporary security and diplomatic issues back to the 1961–1978 U.S.–Japan negotiations involving secret arrangements in the reversion of Okinawa, Japan’s defense build-up, including the question of Japan’s nuclear option, and U.S.–Japan defense cooperation. Through a systematic assessment of the behind-the-scenes discussions, Dr Yukinori Komine demonstrates that external security calculations were consistently primary factors in U.S.–Japan relations. The book concludes by making policy-relevant suggestions, important for the "Pacific Century". This book offers crucial contributions to the ongoing debate regarding the increasing need for greater transparency and burden-sharing in the U.S.–Japan alliance. It will appeal to scholars and students of International Relations of the Asia-Pacific region, East Asia–U.S. relations, U.S. Politics and Japanese Politics, as well as Foreign Policy.