The Leo Gallagher Collection is divided into five series: PERSONAL, J.B. MCNAMARA, CASES, INVESTIGATIONS, POLITICAL INTERESTS, and ELECTION CAMPAIGNS. The PERSONAL series contains biographical material, including correspondence and other material from Gallagher's passport denial in 1953. Also of interest is a copy of a speech on racism delivered by Gallagher at a meeting in 1947, and letters from him to the editor of People's World. The J.B. MCNAMARA series contains an exchange of letters between Gallagher and McNamara, a labor activist sentenced to life in prison for his part in the bombing of the Los Angeles Times building in 1910. Included are clippings from this period on McNamara and the Times bombing.  CASES is the third series in the collection, and it contains notes, clippings, court related documents, and letters pertinent to some of the many court trials Gallagher was either involved with or had an active interest in. There are letters to elected government officials and foreign diplomats to whom he expressed his views or his concern for the treatment of defendants. This series also contains material related to the German Reichstag Fire trial, and material collected by Gallagher when he toured Nazi Germany from August, 1933 until his deportation as an undesirable alien in February, 1934. An interesting case handled by Gallagher in 1945-1946 that involved the deportation of 200 Indonesian seamen that refused to re-board Dutch or British ships for political reasons is also represented here. The series INVESTIGATIONS contains affidavits from victims of police brutality in Los Angeles County from 1935 through 1938. There is material related to the investigation Gallagher was appointed by Governor Culbert L. Olsen to chair, that concerned a 13-year-old inmate's apparent suicide at the Whittier State School for Boys in 1939. The series also contains correspondence and materials from Gallagher's 1937 trip to Republican Spain as part of a delegation to inspect state operated children's homes established to protect the young from the effects of the civil war. The last series in the collection, POLITICAL INTERESTS, contains correspondence between Gallagher and Catholic clergy, government officials, and diplomats on U.S. domestic and foreign policy, communist teachings, and theology. There are class schedules and ephemera from some of the early Los Angeles workers' schools from the late-1940s, and catalogs, schedules, and correspondence from the California Labor School, 1948 and 1949. The series also contains campaign fliers, brochures, pamphlets, and related materials connected to Gallagher's various election campaigns.