Foreword.-  Many factors combined to make the assault on Peleliu one of the least understood operations of World War II. Yet it was one of the most vicious and stubbornly contested, and nowhere was the fighting efficiency of the U.S. Marine more convincingly demonstrated.

At Peleliu the enemy proved that he had profited from his bitter experiences of earlier operations. He applied intelligently the lessons we had taught him in the Solomons, Gilberts, Marshalls, and Marianas. At Peleliu the enemy made no suicidal banzai charges to hasten the decision; he carefully concealed his plans and dispositions. He nursed from his inferior strength the last ounce of resistance and delay, to extract the maximum cost from his conquerers. In these respects Peleliu differed significantly from previous campaigns and set the pattern for things to come: Iwo Jima and Okinawa.

Because the operation protracted itself over a period of nearly two and a half months, it is easy to lose sight of the fact that the strategic objective was accomplished within the first week: neutralization of the entire Palaus group, and with this, securing of the Philippines approaches.

C. B. CATES, 
GENERAL, U.S. MARINE CORPS, 
COMMANDANT OF THE MARINE CORPS.

Preface.- THE ASSAULT ON PELELIU is the seventh in a series of operational monographs, based on official sources and documented in detail, being prepared by the Historical Division, Headquarters, U.S. Marine Corps. The purpose of these monographs is to afford the military student as well as the casual readers a factually accurate study of the several Marine Corps operations in World War II. Upon completion of the series, it is planned to edit the individual pieces into a complete operational history of Marine campaigns in the Pacific.

As initially conceived, seizure of Peleliu would constitute only one phase of a many-sided operation (designated STALEMATE) against the western Carolines, embracing at one time or another capture of all the Palaus group, Yap and Ulithi. Subsequent revisions of the original plan, however, raised Peleliu from a secondary target to the primary one, precipitating one of the most bitterly contested campaigns in the entire Pacific war, beside which the concurrent seizures of Angaur and Ulithi were largely incidental. Because Marine assault echelons were committed nowhere else, operations on Peleliu are discussed in fine detail, whereas those elsewhere are merely summarized to round out the strategic picture as a whole.

This manner of treatment is complicated somewhat by the participation of U.S. Army elements, especially the 81st Infantry Division. Believing that Army agencies are better qualified to deal with strictly Army operations, and would prefer doing so, we have described these herein only in sufficient detail to reveal their essential nature. An exception is made in those instance when Army units fought directly beside the Marines, attached operationally under over-all Marine command, as was the case with Regimental Combat Team 321 on Peleliu.

Many individuals and agencies contributed to the compilation of this monograph. To the more than 100 participants in the actual operation who furnished comment, corrections and elaborations, grateful acknowledgment is made herewith. Special gratitude is extended to Office of Naval History, Naval Records and Library, and Office of the Chief of Military History, Department of the Army: in particular Dr. Philip A. Crowl and Mr. Robert R. Smith of the Pacific Section. Maps were prepared by Reproduction Department, Marine Corps Schools, Quantico, Virginia. Official U.S. Marine Corps photographs have been used except as otherwise noted.

BRIGADIER GENERAL, U.S. MARINE CORPS, 
DIRECTOR OF MARINE CORPS HISTORY.