The Army and Economic Mobilization was written on the basis of a wide variety of source materials located chiefly in various offices and agencies of the Department of Defense in and around Washington, D. C. The principal sources of information were governmental records, especially those of the War Department--the senior predecessor of the Department of Defense. Nongovernmental records--books, periodicals, and other publications--also supplied valuable insights and information.
The records of the United States Government in the mid-20th century have become so voluminous and heterogeneous in character that the methods and tasks of the historian working in this area have undergone a substantial revolution. The graduate historiographer at the beginning of the century was a kind of Sherlock Holmes--a trained sleuth skilled in the art of extracting a maximum of reliable information from a paucity of sources. Today, in the complex field of governmental operations and policy, the age of scarcity is past, and the historian is faced with a bewildering superabundance of documentary materials which must somehow be surveyed, abstracted, studied, comprehended, evaluated, and appropriately synthesized into a readable summary--all within a period considerably shorter than a single lifetime.
In this milieu the historian of government policy and administration is interested first and foremost in documents containing the highest yield of significance per page. Such documents are typically the general reports and summaries, the major directives and manuals, the books of regulations, codes, and statutes which reveal the basic tasks, methods, and accomplishments of those responsible for forming and executing governmental policy. Documents of this type, devised during the course of actual operations in order to appraise, influence, and control the general trend of events in the relevant areas, are primary sources par excellence. As indicated in footnote citations herein, the present volume relies heavily upon such sources.
A second important class of primary documents consists of those which collectively reveal in detail the multitudinous pressures, problems, and other reasons for the formulation and development of specific policies. These documents are the countless individual memoranda, letters, telegrams, notes, clippings, abstracts, forms, diaries, logs, studies, exhibits, tabulations, ad hoc reports, and other materials found in the operating files of the numerous offices and agencies involved during the time period in question. These primary sources are of a lower order of generality than those described in the preceding paragraph, but they are indispensable to a genuine understanding of the origins, nature, and consequences of the general policies and procedures under review. Inevitably, only a minute fraction of these materials can be perused by a single investigator.
Under these circumstances it is fortunate for students of America's World War II experience that an official governmental historical program was firmly established by the President at the beginning of the late war. This program forced the preparation of historical reports and summaries by every