This history, which traces the development of helicopters in the Marine Corps from 1946 to 1962, offers a tribute to the creative vision and planning of a handful of Marine officers who conceived of the vertical assault concept in amphibious operations at a time when suitable aircraft to make it work did not exist. The story of the subsequent struggle to procure and develop those aircraft, to refine a doctrine for their employment, and to familiarize the Marine Corps with their use is an interesting and vital part of modern Marine Corps history. The documentary basis for this monograph was primarily the official records of the Marine Corps and Navy Department, but considerable use was made of interviews and correspondence with key individuals involved in all phases of helicopter development.