The Institute holds more than eight million items, including books, periodicals, military publications, manuscripts, photographs, and maps relating to military history. No other agency has as extensive a collection relating exclusively to the role of the military n the development of the United States from the colonial period to the present. In addition to purely military matters, coverage includes fields such as international relations, law, science and technology, sociology, medicine, explorations, economics, geography, political science, and literature. Original sources are a vital part of the Institute's holdings. Some of the Institute's services include inter-library loans and remote electronic access of significant bibliographic material.
Several databases describe portions of the manuscript and photograph archives.
Plans are currently underway for a major digital archive with full-text retrieval of documents. A Guide to the Study and Use of Military History by John E. Jessup, Jr., and Robert W. Coakley, editors.