Consists of documents, photographs, newsclippings, correspondence and other materials related to the 1916 Preparedness Day Bombing in San Francisco. Materials also include bound trial transcript volumes, a copy of Estolv E. Ward's manuscript, The Gentle Dynamiter (later published), an unpublished manuscript by Thomas M. McDade on the case, and additional research files on violence and labor defense, particularly related to the history of the United Mine Workers.