Many people today seek an expansion of mind through the use of psychedelics. So what other worlds, intelligences and entities are being encountered and sought in such experiences? In this Sheldrake-Vernon Dialogue, Rupert Sheldrake and Mark Vernon discuss psychedelics and spiritual paths. They ask why they are of such interest now. They explore the effects they have and how these relate to other altered states of consciousness, from dreams and divine encounters to inspired visions. They ask how these experiences can be transformative, and whether they can be accessed in other ways. What dangers might be encountered, both psychological and spiritual, and what can be learnt from ancient mystery traditions and the ecstatic journeys charted by writers from Plato to Dante?