Ronald Hutton, Professor of History at the University of Bristol, delivers this Gresham College lecture on the Greek god Dionysius as part of his Dodgy Deities series, focusing on cult practice rather than myth. He traces Dionysus as a vegetation and agricultural god, patron of Athenian festivals and theatre, and the deity whose wine made him both a great leveller and a source of madness, violence and transgression, embodied in the maenads. Hutton covers the Bacchic scandal that rocked Rome in 186 BCE, the Dionysian mystery religion, and the god's associations with death and the afterlife. Recorded at Barnard's Inn Hall in London, the talk builds toward the question of whether any unifying logic connects Dionysus's wildly contradictory attributes, from convivial host to leader of what Hutton calls the hippies from hell.