After being identified to the House Un-American Activities Committee by another screenwriter,
Richard Collins,
Victor Navasky estimated of the number he implicated at 161 and wrote that many of his identifications were inaccurate. Among those Berkeley said attended a meeting of party members at his house was
Lillian Hellman. Berkeley has been called HUAC's "number-one friendly witness" because he provided more names and more thorough documentation than any other witness. He gave the committee so many names that a Hollywood joke said he was simply replicating the membership list of a club frequented by Hollywood celebrities. HUAC investigator William Wheeler reportedly told Berkeley that he was providing more names than they needed: "Don't name that many. You're just going to get yourself in big, deep trouble." He painted a particularly negative portrait of writer
John Howard Lawson as the "grand Poo-Bah of the Communist movement" who "speaks with the voice of Stalin and the bells of the Kremlin." Berkeley was represented by
Edward Bennett Williams, who had close ties to many enthusiasts of the anti-Communist campaign of the
McCarthy era. Following his testimony, Berkeley became a member of an organization formed to expose Communist influence in the entertainment industry, the
Motion Picture Alliance for the Preservation of American Ideals (MPA). ==References==