Mary C. McCall Jr. was the Screen Writers Guild’s most valuable asset from its earliest days through the blacklist. Eventually, she would publicly sacrifice her career in Hollywood defending the basic right of screen credit against a new breed of politically repressive producers. But, like her most famous creation, Maisie Ravier, McCall did not give up on herself or her show business industry. Sadly, over the years, the guild and historians of Hollywood have denied her the screen credit she deserves. She was one of the most politically active and powerful of all Hollywood writers, and yet is one of the least discussed in scholarly accounts of the film industry. Though much of the scholarship on studio-era Hollywood screenwriters has focused on the men who led the Hollywood Left, during the studio era, McCall wielded more power than any Hollywood woman before or since. This is her story.