This thesis traces the development of doctrine for command relationships in amphibious warfare. The study examines the command relationships employed in landing operations through World War I, with emphasis on Santiago in the Spanish-American War and Gallipoli in World War I as the driving forces behind joint and naval doctrine development. From this background, the thesis outlines the efforts of the Joint Board and Marine Corps Schools to codify their doctrine, primarily in the interwar years. The joint process led to Joint Action of the Army and the Navy and Joint Overseas Expeditions of 1927 and 1933, predecessors to Joint Publication 0-2, Unified Action Armed Forces. Naval doctrine begun by the Marine Corps Schools became the Navy's Fleet Training Publication 167, Landing Operations Doctrine, U.S. Navy, 1938, predecessor to Joint Publication 3-02, Joint Doctrine for Amphibious Operations. The thesis then examines the employment of that doctrine, and the doctrinal changes and lessons that resulted, in three major amphibious operations, WATCHTOWER (Guadalcanal), ICEBERG (Okinawa), and CHROMITE (Inchon). The study concludes with a discussion of the relevance of the historical development to today's doctrinal issues and provides recommendations for further research.