This is the book from which Jim Morrison’s band took its name. The title comes from a line by the English visionary and poet, William Blake: “If the doors of perception were cleansed every thing would appear to man as it is, infinite.”

Huxley decides to test Blake’s theory by dosing himself on mescaline, the hallucinogenic ingredient in peyote. Huxley seems to have been inspired by the peyote ceremonies of Native American tribes, who consider the cactus a spiritual gift from God.