The author looks at the first occasion on which the United States became involved in war while fulfilling its obligations under the United Nations Charter: the Korean episode. This book is concerned principally with the interrelation of United States policies and those of the United Nations as they developed in Korea. It attempts to explain in what fashion and to what extent American policies with respect to Korea were modified by membership in the United Nations, and conversely, how United Nations policies were affected by the fact of American membership.