The Jefferson School of Social Science was an adult education institution of the Communist Party USA located in New York City. The so-called "Jeff School" was launched in 1944 as a successor to the party's New York Workers School, albeit skewed more towards community outreach and education rather than the training of party functionaries and activists, as had been the primary mission of its predecessor. Peaking in size in 1947 and 1948 with an attendance of about 5,000, the Jefferson School was embroiled in controversy during the McCarthy period including a 1954 legal battle with the Subversive Activities Control Board over the school's refusal to register as a so-called "Communist-controlled organization."
https://en.wikipedia.org/wiki/Jefferson_School_of_Social_Science