The American Library Association (ALA) is a nonprofit organization based in the United States that promotes libraries and library education internationally. It is the oldest and largest library association in the world.

The Library War Service was established by the American Library Association in 1917 to provide library services to American soldiers training in camps and serving overseas in World War I. ALA President Walter Lewis Brown initiated a partnership between the American Library Association and the Library of Congress. Between 1917 and 1920, the ALA raised $5 million from public donations, erected 36 camp libraries, distributed 7 to 10 million books and magazines, and provided library collections to more than 500 locations, including military hospitals. The Library War Service also provided books in Braille to soldiers that were blinded in battle. Library War Service librarians wore uniforms, similar to those worn by other volunteer groups like the American Red Cross, and the Library War Service provides some of the earliest examples of women participating in uniformed war service overseas. Millions of public libraries in the United States also participated in Library War Service activities, serving as collection points for books as well as places to organize and promote the War Service campaign. The efforts of the Library War Service eventually led to the creation of many modern library services, including the creation of library departments in the Army, Navy, Veterans' Association and Merchant Marine, as well as the establishment of the American Library in Paris, which remains the largest English-language lending library on the European continent today.