Columbia subject headings:
Communism--United States.
Hoover, J. Edgar (John Edgar), 1895-1972.
Subversive activities--United States--History--20th century.
United States. Congress. House. Committee on Un-American Activities--History--20th century.
United States. Federal Bureau of Investigation--History--20th century.
Harvard subject headings:
Communism--United States--1917-
Hoover, J. Edgar (John Edgar), 1895-1972
Subversive activities--United States--History--20th century
United States. Congress. House. Committee on Un-American Activities--History--20th century.
United States. Federal Bureau of Investigation--History--20th century.
Princeton subject headings:
Communism--United States.
Hoover, J. Edgar (John Edgar), 1895-1972.
Subversive activities--United States--History--20th century.
United States. Congress. House. Committee on Un-American Activities--History--20th century.
United States. Federal Bureau of Investigation--History--20th century.