Harold Buchman was a 20th-Century American Communist attorney, "the most important communist member" of the Progressive Citizens of America (founded by former vice president Henry A. Wallace, president of the Roosevelt Democratic Party Club, and treasurer for the Screen Writers Guild.  
His name appeared in the earliest Hollywood blacklist: a list of Communist sympathizers along with Dalton Trumbo, Maurice Rapf, Lester Cole, Howard Koch, John Wexley, Ring Lardner Jr., Harold Salemson, Henry Meyers, Theodore Strauss, and John Howard Lawson. 
On April 17, 1947, Buchman, actress Anne Revere, and writer Sam Moore pled the Fifth Amendment regarding questions about Communist affiliation. 
In January 1948, Buchman announced the Wallace for President Committee. In February 1948, he became new executive secretary and Maryland state director of the Progressive Party. In Summer 1948, when the Maryland attorney general rejected all filings by Progressive candidates for failure to sign loyalty oaths, Buch announced he would file a suit. 
In June-July 1951, Buchman counseled the follow out of more than 40 people subpoena-ed by HUAC: Joseph Henderson and Philip Gran (June 21, 1951), Robert W. Lee (June 26, 1951), Irving Kandel (June 27, 1951), Sam Fox and Howard Bernard Silverberg (June 28, 1951), Louis Julius Shub (July 12, 1951), and Milton Seif and Irving Winker (July 13, 1951). 
In March 1952, Buchman defended: Maurice Braverman, George Meyers, Roy Wood, Dorothy Rose Blumberg (wife of Albert Blumberg), Philip Frankfeld, and Regina Frankfeld (all members of the Communist Party branch of Maryland and the District of Columbia). 
In 1971, Buchman defended Arthur F. Turco, Jr., a New York lawyer charged in connection with the 1969 torture and murder of a suspected Black Panthers police informer. 
Anne Revere was an American actress and a liberal member of the board of the Screen Actors' Guild. She was best known for her work on Broadway and her film portrayals of mothers in a series of critically acclaimed films. An outspoken critic of the House Un-American Activities Committee, her name appeared in Red Channels: The Report on Communist Influence in Radio and Television in 1950 and she was subsequently blacklisted.
The National Guardian, later known as The Guardian, was a left-wing independent weekly newspaper established in 1948 in New York City. The paper was founded by James Aronson, Cedric Belfrage and John T. McManus in connection with the 1948 Presidential campaign of Henry A. Wallace under the Progressive Party banner. Although independent and often critical of all political parties, the National Guardian is thought to have been initially close to the ideological orbit of the pro-Moscow Communist Party USA, but this suspected association quickly broke down in the course of several years.
The Committee for the First Amendment was an action group formed in September 1947 by actors in support of the Hollywood Ten during the hearings of the House Un-American Activities Committee (HUAC). It was founded by screenwriter Philip Dunne, actress Myrna Loy, and film directors John Huston and William Wyler.
Howard E. Koch was an American playwright and screenwriter who was blacklisted by the Hollywood film studio bosses in the 1950s.
Sidney Robert Buchman was an American screenwriter and film producer who worked on about 40 films from the late 1920s to the early 1970s. He received four Oscar nominations and won once for Best Screenplay for fantasy romantic comedy film Here Comes Mr. Jordan (1941) along with Seton I. Miller.
Michael Gordon was an American stage actor and stage and film director.
Mary R. Stalcup Markward was for seven years a member of the Washington, DC "District Communist Party" as director of the party's membership. She was actually working undercover for the FBI.
The United States Progressive Party of 1948 was a left-wing political party in the United States that served as a vehicle for the campaign of Henry A. Wallace, a former vice president, to become President of the United States in 1948. The party sought racial desegregation, the establishment of a national health insurance system, an expansion of the welfare system, and the nationalization of the energy industry. The party also sought conciliation with the Soviet Union during the early stages of the Cold War.
Irving Pichel was an American actor and film director, who won acclaim both as an actor and director in his Hollywood career.
Progressive Citizens of America (PCA) was a social-democratic and democratic socialist American political organization formed in December 1946 that advocated progressive policies, which worked with the Congress of Industrial Organizations (CIO) and allegedly the Communist Party USA (CPUSA), as a precursor to the 1948 incarnation of the Progressive Party. It also led to formation of a counter group called Americans for Democratic Action (ADA), formed in January 1947 with progressive domestic views but anti-communist and interventionist foreign policy views, that split liberals and nearly cost Harry S. Truman the 1948 US Presidential Election. The organization was dissolved in 1948.
The Hollywood blacklist was an entertainment industry blacklist, broader than just Hollywood, put in effect in the mid-20th century in the United States during the early years of the Cold War. The blacklist involved the practice of denying employment to entertainment industry professionals believed to be or to have been Communists or sympathizers. Actors, screenwriters, directors, musicians, and other American entertainment professionals were barred from work by the studios.
Maurice Harry Rapf was an American screenwriter and professor of film studies. His work includes the screenplays for early Disney live-action features Song of the South (1946) and So Dear to My Heart (1949), uncredited work on the screenplay for the animated feature Cinderella (1950), and several films of the late 1930s. He was a co-founder of the Screen Writers Guild. He was blacklisted in 1947 due to his association with the Communist Party USA. He later taught film studies at Dartmouth College.
Trumbo is a 2015 American biographical drama film directed by Jay Roach and written by John McNamara. The film stars Bryan Cranston, Diane Lane, Helen Mirren, Louis C.K., Elle Fanning, John Goodman, Michael Stuhlbarg as Edward G. Robinson, Dean O'Gorman as Kirk Douglas, and David James Elliott as John Wayne. The film follows the life of Hollywood screenwriter Dalton Trumbo, and is based on the 1977 biography Dalton Trumbo by Bruce Alexander Cook.
Joseph Forer was a 20th-century American attorney who, with partner David Rein, supported Progressive causes, including discriminated communists and African-Americans. Forer was one of the founders of the National Lawyers Guild and its DC chapter. He was also an expert in the "Lost Laws" of Washington, DC, enacted in 1872–1873, that outlawed segregation at business places.
Maurice Braverman (1916–2002) was a 20th-century American civil rights lawyer and some-time Communist Party member who was convicted in 1952 under the Smith Act, served 28 of 36 months, then immediately faced disbarment, against which he fought in the 1970s and won reinstatement in Maryland (1974) and federal courts (1975).
Counterattack was a weekly subscription-based, anti-communist, mimeographed newsletter, which ran from 1947 to 1955 and was published by a "private, independent organization" of the same name and started by three ex-Federal Bureau of Investigation agents.
The Communist Party of Maryland is the regional party of the Communist Party USA in the state of Maryland. Maryland's Communist Party was founded in 1919, the same year as the national party was founded, and is still in operation with its headquarters in Downtown Baltimore.
The National Committee to Defeat the Mundt Bill AKA "NCDMB" (1948-1950) was an American organization that sought to oppose passage of the Mundt-Nixon Bill and subject of a 15-page report of the House Un-American Activities Committee, two of whose members were US Representatives Karl E. Mundt and Richard M. Nixon.
Edward Huebsch, AKA "Eddie Huebsch" and "Ed Huebsch," (1914-1982) was a 20th-century American Communist screenwriter whose career was cut short by the Hollywood blacklist.
Al Lannon (1907-1969), born Albert Vetere, was an Italian-American leader in the Communist Party USA and a co-founder of the National Maritime Union (NMU), best known for organizing and activism for American labor unions on behalf of merchant mariners and stevedores (1930-1955).