_In the fall of 1949 Senator McMahon directed the staff of the Joint Congressional Committee on Atomic Energy to study the hydrogen bomb in relation to international control of atomic energy. The material in the following pages, with the exception of the comments in Appendix D, was prepared by the staff at the chairman’s request to assist the joint committee in considering the problem._ _It is my belief that this valuable material, until now unavailable in such excellent summary form, will also assist Americans in general in considering this vital problem. Readers of this volume should find it helpful in arriving at conclusions of their own, particularly in the light of the facts and discussion presented in Chapters III and IV. I further believe that a careful perusal of the following material will lend strong support to my view that the international control of atomic weapons, as envisaged in the majority plan of the United Nations,—the only plan that may give assurance against a surprise atomic attack—had become wholly impractical even before the entry of the H-bomb into the picture, and that the imminent development of the H-bomb has made it so unworkable that any further plan to revive it would be futile._ _This material makes it clear (a) that Russia never had any intention of reaching any agreement on international control and had set out to sabotage any plan from the very beginning; and (b) that no plan, no matter how foolproof, could hope to succeed in the absence of complete mutual trust and confidence. Events in Korea, I am convinced, have driven the last nail into the coffin of the UN control plan._ A SIGNIFICANT EVENTS IN THE HISTORY OF INTERNATIONAL CONTROL OF ATOMIC WEAPONS May 1945: Secretary of War Stimson appoints interim Committee to study problem of atomic energy. August 6, 1945: Hiroshima. October 3, 1945: President’s message to Congress outlines necessity for international control of atomic energy and proposes conversations with Canada and United Kingdom. November 15, 1945: Three-nation agreed declaration on atomic energy (Truman-Attlee-King declaration). Calls for United Nations Commission to make proposals for international control plan. Proposals should provide safeguards “by way of _inspection and other means_.” (Wherever used in the following pages, italics are supplied.) December 27, 1945: U.S.-U.K.-U.S.S.R. Foreign Minister communiqué on results of Moscow Conference. Proposes that Canada, China, and France join with Big Three in sponsoring resolution calling for United Nations Atomic Energy Commission with terms of reference stipulated in Truman-Attlee-King declaration. January 24, 1946: General Assembly resolution establishing United Nations Commission on Atomic Energy. Composed of members of Security Council plus Canada.