My guest on this week's Book Club podcast is the writer, artist and historian Amy Jeffs. Her new book Saints: A New Legendary of Heroes, Humans and Magic aims to recover and bring back to life the wild and fascinating world of medieval saints. She tells me what we lost with the Reformation (all the good swearing, among much else), what was the difference between magic and a miracle, and how what washes up on the Thames foreshore can give us the entry point to a whole vanished imaginarium.