In 1950, fewer than 50,000 Americans out of a total US population of 150 million were members of the Communist Party. Yet in the late 1940s and early 1950s, American fears of internal communist subversion reached a nearly hysterical pitch. Government loyalty boards investigated millions of federal employees, asking what books and magazines they read, what unions and civic organizations they belonged to, and whether they went to church. Hundreds of screenwriters, actors, and directors were blacklisted because of their alleged political beliefs, while teachers, steelworkers, sailors, lawyers, and social workers lost their jobs for similar reasons. More than thirty-nine states required teachers and other public employees to take loyalty oaths. Meanwhile, some libraries pulled books that were considered too leftist from their shelves. The banned volumes included such classics as Robin Hood, Henry David Thoreau’s Civil Disobedience, and John Steinbeck’s The Grapes of Wrath.