This series represents the bulk of the collection, and includes over 300 different titles published by a large array of organizations. Many titles only include one or two issues, while a few have more complete runs. Titles with a significant number of issues include The Militant (Militant Publishing Company, Socialist Workers Party), The Movement (Student Non-Violent Coordinating Committee and Students for a Democratic Society), The Newsletter (Socialist Labor League), Seattle Gay News (Gay Community Center), and Sojourner (Sojourner Feminist Institute). Publishers with multiple titles include the International Defence and Aid Fund for Southern Africa, the National Lawyers Guild, the United Secretariat of the Fourth International, the National Organization for Women, a variety of Leonard Peltier support groups, and others. Publishers are based both in the U.S. and internationally, and the cities of Seattle, New York, and Boston are particularly well represented. Major subjects in this series include socialism, Trotskyism and Marxism, civil rights, the early feminist and lesbian movements, gay liberation, indigenous organizing, and prisoners' issues.

This series includes a small number of pamphlets published by a variety of organizations, including the Liberation Support Movement Information Center, Pathfinder Press (Socialist Workers Party), Peoples Democracy and the Communist Party. Subjects addressed include socialism, Trotskyism and revolutionary organizing, civil rights, gay liberation, and others. International issues in countries including Angola, Ireland and South Africa are included. There are also a small number of directories and U.S. government publications.

This series contains subject files, which are comprised of newspapers and pamphlets that were arranged topically by the Freedom Socialist Party and Radical Women. Newspaper titles, and even individual issues, included in Series I may also be found in this series. The subjects included in Series III are representative of the collection as a whole, with additional emphasis on international issues.