“U.S. Marines in Lebanon, 1982-1984,” is based primarily on the monthly command chronologies and biweekly situation reports of the Marine amphibious units which were deployed to Lebanon as well as other related official documentation, all of which resides in the archives of the Marine Corps Historical Center. Although none of the information in this history is classified, some of the documentation on which it is based remains so. A considerable number of "issue-oriented" oral history interviews concerned with the deployments were also used in the preparation of this book. Following the return of the 32d MAU from Lebanon and before its redeployment in early 1983, the author began a series of interviews with the key personnel in all the MAU s deployed to Lebanon to augment the paper record of this 18-month period in Marine Corps history. Before U.S. Marines in Lebanon was completed, a total of 119 interviews had been conducted. They are now accessioned in the Marine Corps Oral History Collection. This book is a straightforward account of the deployment of Marines to Lebanon in the period 1982-1984. The story begins with the landing of the 32d Marine Amphibious Unit (32d MAU) in Beirut in August 1982 at the request of the Lebanese Government to assist, together with French and Italian military units, in supervising the evacuation of the Palestine Liberation Organization . It ends in February 1984 with the withdrawal of the 22d Marine Amphibious Unit following the effective end of its mission and the nearly complete breakdown of order in Lebanon. In between is an ambiguous Marine mission of presence of 18 months' duration. Together with the British, French, and Italian members of the Multi-National Force, the Marines attempted, as "peacekeepers," to assist the Lebanese Government in achieving stability and ending the factional fighting which has all but destroyed Lebanon as a viable political entity. For any number of reasons, none of which are the concern of this book, the mission of peacekeeping failed, and in the process, those who were there to help Lebanon achieve the peace so many Lebanese wanted—but too many others did not—were sorely tried and severely mauled. As a history strictly of the Marines' role in Lebanon, this book does not deal with the major, high-level decisions of the administration which put and kept Marines in that country. Nor does the book deal with American diplomatic efforts in the Middle East in this period except in those instances when the MAU Marines were directly involved. This is simply the story of Marine Corps presence and operations in Lebanon for the period concerned. It draws no conclusions.