The Marriage of Heaven and Hell "A Memorable Fancy" plate 14 (1790 - 1793). Inspired the title of Aldous Huxley's 1954 book about drug experimentation, The Doors of Perception, which in turn inspired the name of the 1960s rock group The Doors.
Bhante Henepola Gunaratana (2010). “Beyond Mindfulness in Plain English: An Introductory Guide to Deeper States of Meditation”, p.43, ReadHowYouWant.com