“Creepy ideas just pop into my head,” wrote crime novelist Patricia Highsmith in her diary, illuminated for the first time by Swiss filmmaker Eva Vitija in this elegant documentary. Highsmith chased success with crime novels like The Talented Mr. Ripley and Strangers on a Train, while using a pen name for Carol, the rare 1950s novel to give lesbians a happy ending. Highsmith’s personal life was fully queer; interviews with her surviving girlfriends deliver tasty gossip (“she had a staggering amount of conquests”) and an acidic backstory (“her mother was a bitch”).

Gwendoline Christie (Game of Thrones) superbly voices the diaries (which Highsmith covered in curses and warnings to potential snoops). Exploratory sex with men, she wrote, was “like steel wool in the face.” A married woman she followed to England was “beauty, perfection, completion.” Late in life she unmasked herself as Carol’s author, attracting a new generation of fans. Loving Highsmith reveals an essential lesbian artist who never stopped writing about murder and death, but never gave up on happiness.