"The Number of the Beast" is a song by Iron Maiden which is based on the movie Damien: Omen II.
Before the music starts, this opens with an a cappella quote from The Book of Revelation. The band wanted the horror film actor Vincent Price to read this intro, but he wanted more money than they were willing to pay (a year later, Price lent his voice to Michael Jackson's "Thriller"). The quote was read by an unknown thespian actor who had no interest in the band. (thanks, Jeff - Haltom City, TX, for above 2)
The number of the beast, according to Revelation 13:18 (the quoted scripture), is 666. Interestingly, 6+6+6 is 18, the number of the verse. Elsewhere in that chapter, it is stated that no man will be able to buy or sell without a mark on the right hand or forehead with the number of the beast on it. This has lead to religious zealots "finding" 666 in practically everything.
The cover art for the album depicted Iron Maiden's mascot Eddie and a devil in vicious combat in Hell. The cover art for single depicted Eddie with a sinister grin on his face holding the devil's head (See also: "Run to the Hills").
During the recording of the album, there were rumors floating about that supernatural occurrences had been going on in the studio, such as lights flipping on and off, strange noises, visions of Satan, etc. This was used as evidence that Satan and the Antichrist had a hand in making this. In a concert at New York's Palladium on June 29, 1982 (which is heavily bootlegged), Bruce Dickinson said: "Just want to say to all the people who play records backwards and burn albums out in the streets, they can go and get... stick their heads up their arse or something like that, 'cause... we ain't interested."
On the cover art, just right of the devil's ankle, is artist Derek Riggs' signature: the unique symbol which contains his initials.
Steve Harris: "Basically, this song is about a dream. It's not about devil worship."
The tour accompanying the album's release was called "The Beast on the Road."
Bruce Dickinson: "We can play with conviction every night, because we totally believe in the music we're performing." This quote, along with the line "666, the one for you and me" led many preachers and enemies of rock music to believe Maiden were Satanists. (thanks, Brett - Edmonton, Canada, for above 7)
This was used in the soundtrack for Tony Hawk's Pro Skater 4.
This was re-released as a single in the UK in January 2005. This time, it went to #3. (thanks, Tom - Trowbridge, England, for above 2)
As he explained on the BBC Classic Albums series, Bruce Dickinson's high-pitched scream at the end of the intro was a result of producer Martin Birch forcing the band to replay the intro several times. Dickinson became so fed up with the constant repeats that he emitted the scream out of frustration, and it fit so well that the band decided to keep it. (thanks, Alex - Redford, MI)