PIHKAL (Phenethylamines I Have Known And Loved) is a unique book written by renowned psychopharmacologist Alexander Shulgin and his wife Ann Shulgin. This book gives details of their research and investigations into the use of psychedelic drugs for the study of the human mind, and is also a love story. The second half of the book describes in detail a wealth of phenethlyamines, their physical properties, dosages used, duration of effects observed, and commentary on effects.