Madame Blavatsky is no longer a household name, but her ideas changed the course of history. A central figure in Victorian Spiritualism, she is credited with starting the New Age movement. She influenced everyone from Aldous Huxley and H.P. Lovecraft to Aleister Crowley and David Bowie. Even Dungeons & Dragons borrows from Blavatsky. Although her “miracles” were debunked in her lifetime, her ideas were far from harmless—her theories about race heavily influenced the Nazis and may have led to the Holocaust. This week, Jess talks to author and horror expert Sian Ingham about the difficult legacy of Madame Blavatsky. Sian’s books include The Age of Miracles: Essays on the Collapse of History, and the Bram Stoker Award-nominated We Don’t Go Back: A Watcher’s Guide to Folk Horror.