(Includes maps) In all the extensive literature of military history there are but few volumes devoted to the study of logistics. Although the rationalization of army supply is fairly old in the history of warfare the written record normally has been confined to the exposition, in field service regulations and manuals, of how supply, evacuation, and troop movement should be organized, rather than the narrative account of what actually happened in the course of wars and campaigns. The term "logistics" is itself of recent coinage. During World War I, it was confined chiefly to French lexicons, and it remained for World War II and for the American armed forces to give the term meaning and wide usage. Even so the definition of "logistics" is subject to wide variations. As used in the present volume the term covers the supply of armies in the field and the movement of troops to the combat zone. Little attention is given the evacuation of the wounded since other Army historians will tell this story. When plans were made for writing a series of volumes dealing with U.S. Army operations in the European theater during World War II, the importance of the logistical support given the armies in the field literally forced this subject upon those planning the series. It was decided that the story of logistics could not be treated as an appendage within the various volumes dealing with combat operations but would have to be told in the form of a sustained and independent narrative moving from ports and beaches forward to the combat zone. Months of research led to the conclusion that the complexity and scope of logistical history demanded more than a single volume. This volume is the first of two entitled "Logistical Support of the Armies". It is intended that the history herein recounted stand by itself as the complete story of supply operations in Europe. But the thoughtful reader will find his understanding and appreciation of the role of logistics enhanced by referring also to those volumes in the European series which deal with the high command and combat operations.