In this week's Book Club podcast, Sam's guest is Kate Summerscale, here to talk about her latest book The Haunting of Alma Fielding: A True Ghost Story. Kate uses the true story of an eruption of poltergeist activity in 1930s Croydon to give what turns into a thoughtful and poignant look at the mental weather of interwar Britain, and the shifting meanings of the occult in light of new ideas about physics and the psychology of trauma. She tells Sam about the story's enduring mysteries and ambiguities, how spookily it chimed with its historical background - and about flying Bovril and a talking mongoose called Gef.