Short answers, pulled from the story.
Psycho was filmed on a tight budget of $807,000, which Hitchcock personally financed through his own Shamley Productions. The film earned $50 million at the box office worldwide, making it the most commercially successful film of Hitchcock's career. Hitchcock personally earned in excess of $15 million from the picture.
Bernard Herrmann composed the score for Psycho. Hitchcock had requested a jazz score, but Herrmann instead wrote for a string orchestra alone, reasoning that the single-tone color of all strings mirrored the film's black-and-white cinematography. Hitchcock later said that 33% of Psycho's effect was due to Herrmann's music.
Robert Bloch's 1959 novel, on which the film is based, was loosely inspired by Ed Gein, a convicted Wisconsin murderer and grave robber. Like Norman Bates, Gein was a solitary figure in an isolated rural location with a deceased, domineering mother, and had sealed off a room in his home as a shrine to her. Gein was apprehended after killing twice.
Paramount Pictures refused to provide Hitchcock's usual budget and called Bloch's source novel "too repulsive" and "impossible for films." In response, Hitchcock offered to finance the film through his own Shamley Productions, use the crew from his television series Alfred Hitchcock Presents, and shoot in black and white. Instead of his usual $250,000 director's fee, he negotiated a 60% stake in the film negative.
In 1992, the United States Library of Congress deemed Psycho "culturally, historically, or aesthetically significant" and selected it for preservation in the National Film Registry.
The shower scene was shot between the 17th and the 23rd of December, 1959, after Leigh had twice postponed filming. The finished scene runs approximately three minutes. The final shot, an extreme close-up on Marion's eye that zooms in and out, required retakes because the water splashed in Leigh's eyes and the cameraman had to manually focus while moving the camera at the same time.