Nostalgia can be both good and bad—at its best, it manifests in historical reenactment, vintage fashion, and mid-century modern furniture. At its worst, it can drive regressive political policies, fascism, and book bans. But nostalgia itself isn’t a bad thing—it’s a bittersweet, rose-tinted longing for the past, but how did people in the past experience it? In this thoughtful episode, Jess talks to Dr. Agnes Arnold-Forster about historical ideas about nostalgia, nostalgia as a medical condition, and the surprising link to a poltergeist that took the form of a talking mongoose called Gef. Dr. Arnold-Forster’s new book is Nostalgia: A History of a Dangerous Emotion.