PIHKAL (Phenethylamines I Have Known And Loved) is a classic in the psychedelic genre by psychopharmacologist Alexander "Sasha" Shulgin, co-authored with his partner Ann, which provides details of his research, synthesis, and investigations into the use of a range of psychedelic compounds for the study of the human mind. The book focuses on phenethlyamines and explores their physical properties, dosages used, and duration of effects observed, and commentary.