PiHKAL: A Chemical Love Story is a book by Dr. Alexander Shulgin and Ann Shulgin, published in 1991. The subject of the work is psychoactive phenethylamine chemical derivatives, notably those that act as psychedelics and/or empathogen-entactogens. The main title, PiHKAL, is an acronym that stands for "Phenethylamines I Have Known and Loved."

Alexander Theodore "Sasha" Shulgin was an American medicinal chemist, biochemist, organic chemist, pharmacologist, psychopharmacologist, and author. He is credited with introducing MDMA, commonly known as "ecstasy", via academic journals and papers to psychologists in the late 1970s for psychopharmaceutical use and for the discovery, synthesis and personal bioassay of over 230 psychoactive compounds for their psychedelic and entactogenic potential.