The Hollywood blacklist—as the broader entertainment industry blacklist is generally known—was the practice of denying employment to screenwriters, actors, directors, musicians, and other American entertainment professionals during the mid-20th century because of their suspected Communist sympathy or membership in the Communist Party. Artists were barred from work on the basis of their alleged membership in or sympathy with the Communist Party USA or refusal to assist investigations into the party's activities. Even during the period of its strictest enforcement, the late 1940s through the late 1950s, the blacklist was rarely made explicit or verifiable, but it directly damaged the careers of scores of individuals working in the film industry.