Marine Corps contributions to the development of doctrine, tactics, and techniques of amphibious warfare have been cited in various Marine Corps histories for at least the past 70 years. It was the idea of Lieutenant General James M. Masters, Sr., then Commandant of Marine Corps Schools, 1966—1968, to restate these contributions and to cite some other contributions such as the doctrine of vertical envelopment and the use of helicopters in land warfare. My idea was to tell the story of these contributions without using a chronology of Marine "firsts." The book is generally divided into decades giving the status of the Marine Corps during the particular decade, coupled with a brief introduction into the political and economic climate of the times. This was of course important because it is those economic and political factors that directly affected the military situation. In researching for the story, three unique things became apparent. The first was that in 1932, the Marine Corps Schools at Quantico chose to study a case history in disaster from World War I, the Gallipoli-Dardanelles Campaign of 1915—16. Rear Admiral L.E.H. Maund, Royal Navy, might have given the answer for Marine Corps Schools if it had been asked of them—Why study Gallipoli? Admiral Maund said of Gallipoli, "It had imagination, it had the promise of great strategic gains; while the reasons for its failure could easily be discerned and had to do with lack of technique, material and belief in this form of warfare—shortcomings that could all be overcome." It is the "shortcomings" that Marine planners had overcome by the commencement of World War II. The second unique accomplishment that surfaced was that Marine Corps Schools had the first written doctrine on landing operations before it had suitable landing boats to carry out the doctrine. In like fashion, within 15 years after the "Tentative Landing Operations Manual" was published, the Marine Corps Schools had the first written doctrine on helicopter operations before actually possessing a helicopter. In this work the fighting record of the U.S. Marine Corps is not discussed but rather the inventiveness of those Marines who pioneered the amphibious role that would be played by the Corps in the 20th century.