This series stresses the League of Nations' main spheres of activity and explores the reasons for its ultimate failure. Among the many topics covered are disarmament, economic cooperation, attitudes of member and nonmember states toward the league, the question of compulsory arbitration of international disputes, controversy over Germany and Soviet entry into the league, and proposals for reform. Many documents allow an in-depth study of the arms negotiations of the 1920s, as well as the events surrounding the Disarmament Conference's eventual failure. The series reproduces considerable material on the league's largely successful involvement with social and economic issues. Series J is edited broadly by subject, though there is necessarily some overlapping. Volume 1 concentrates on general policy statements, mostly from the early years, but also includes accounts and assessments of the League Council's practical work. Volume 2 is similar, with good material on British attitudes and the long effort to gain United States participation. Disarmament is the preoccupation of Volumes 3-6, reflecting its critical importance to the league's mission prior to the Disarmament Conference in early 1932. Emphasis is on land and air arms rather than naval forces. A sampling of translated press reports is included. Volumes 7 and 8, International Disputes and the Machinery of Peace, 1924-1939, focus on many, though not all, of the league's interventions as international arbiter. Volume 9, Legal and Administrative Questions, 1924-1939, brings together material on the codification of international law and the history of the Permanent Court of International Justice (World Court), which with minor adaptations would be continued by the UN up to the present time. Volume 10 of this series summarizes a number of success stories in its economic, social, and humanitarian programs: slavery, housing, traffic in women and children, nutrition, public health, transit and communications, and intellectual cooperation. Most of this work dates from the 1930s, brightening an otherwise bleak period for the league, and it was carried forward after the war by agencies of the UN.