On Hogswatchnight, Discworld's equivalent of Christmas Eve, the Hogfather has gone missing. In his place, Death has donned the red suit and taken up the sleigh, delivering gifts with unsettling literal-mindedness while his level-headed granddaughter Susan investigates who would want to erase a myth. The trail runs back to the Assassins' Guild and something far stranger and colder. Pratchett uses the vanished gift-giver to ask what belief is actually for, why people need to practice believing small lies so they can grasp the large ones. Wry and genuinely moving, it is the Discworld book many readers reach for every winter.