Despite his reputation as a master of scares, Alfred Hitchcock rarely descended into outright horror. He worked in the more respectable genre of "thrillers," rising to the top of Hollywood's A-list with polished films like To Catch a Thief and North by Northwest. But in 1960, he released a film that changed horror forever. Psycho, based on a novel by Robert Bloch and loosely inspired by the real-life Ed Gein serial killer, was something of a passion project for the director.
Source：https://www.cbr.com/how-psycho-changed-horror-genre/
