Question: Iron Maiden's only constant member since their inception was credited for a song on what album?
Context: Stephen Percy "Steve" Harris (born 12 March 1956) is an English musician and songwriter, known as the bassist, occasional keyboardist, backing vocalist, primary songwriter and founder of the British heavy metal band Iron Maiden.  He has been the band's only constant member since their inception in 1975 and, along with guitarist Dave Murray, to have appeared on all of their albums. "Virus" is a single from Iron Maiden, released in 1996.  It is the first single since 1980's "Women in Uniform" that does not appear on any official Iron Maiden studio album.  It was, however, featured as a brand new track on the band's first ever career retrospective — 1996's double-disc "Best of the Beast".  It is the only Iron Maiden song to be credited to both of the band's guitarists.  It has never been performed live by Iron Maiden, but Blaze Bayley performed it several times in his solo career.  Lyrically, the song warns of rising business corruption in an increasingly Internet-dependent world. Iron Maiden is the debut studio album by the English heavy metal band Iron Maiden.  It was issued by EMI on 14 April 1980 in the UK, and a few months later in North America, originally on Harvest/Capitol Records and subsequently Sanctuary Records/Columbia Records in the US.  The North American version also included the song "Sanctuary", previously released in the UK as a non-album single.  In 1998, along with the rest of the band's pre-1995 releases, "Iron Maiden" was remastered with "Sanctuary" added in all territories (but 2015 digital releases and all vinyl reissues use original tracklisting around the globe).  It is the band's only album to feature guitarist Dennis Stratton. Anton Gustafsson tolkar Iron Maiden (Swedish for "Anton Gustafsson Interprets Iron Maiden") is the first and only album by internet celebrity Anton Maiden.  It was released in 1999.  It consists entirely of MIDI covers of songs by the heavy metal band Iron Maiden, with vocals by Anton. Bruce Dickinson, a British heavy metal singer, has released six studio albums, two live albums, one compilations, ten singles, three video albums, fourteen music videos, and one box set.  In 1979, after playing in local groups, Dickinson joined hard rock band Samson.  He departed after two years to become Iron Maiden's lead vocalist.  His debut with this band is considered a "masterpiece", which was followed with a series of top-ten releases.  In 1989, while Iron Maiden were taking a year off, Dickinson and former Gillan guitarist, Janick Gers, composed a song for .  His solo debut, "Tattooed Millionaire" (1990), was an effort that favoured a hard rock/pop metal approach, different from what fans assumed would be an aggressive, Iron Maiden-like album.  Four songs—the title track, "Dive!  Dive!  Dive! ", "Born in '58", and a cover version of David Bowie's "All the Young Dudes"—were released as singles.  Dickinson returned to Iron Maiden, accompanied by Gers as the new guitarist, and the project went on hiatus. " Dive!  Dive!  Live! " was a live video recorded from a concert in Los Angeles, California, in August 1990, and released in July 1991. The Entire Population of Hackney is the name used for a project featuring members of Iron Maiden, FM and Urchin that played two concerts in 1985.  It is also the name used for a bootleg recording of the first show.  It is most notable for being the spark that would lead to Adrian Smith forming his ASAP project later on and ultimately his split with Iron Maiden in 1990 (He returned in 1999 and has since remained a member of the band, although he has pursued other projects).  It is also notable for leading to the first Iron Maiden recording without the current lead singer on lead vocals. Iron Maiden are an English heavy metal band formed by bassist Steve Harris in 1975.  The band's first album, 1980's "Iron Maiden", was written primarily by Harris, with vocalist Paul Di'Anno co-writing two tracks and guitarist Dave Murray contributing "Charlotte the Harlot".  The 1981 follow-up, "Killers", was written almost entirely by the bassist, with frontman Di'Anno contributing only to the title track, "Killers" (the North American bonus track "Twilight Zone" was credited to Harris and Murray).  Bruce Dickinson replaced Di'Anno after the release of "Killers", although he did not contribute any songwriting to "The Number of the Beast", released in 1982, which featured three songs co-written by guitarist Adrian Smith.  "The Number of the Beast" also spawned Iron Maiden's first UK Singles Chart top ten in the form of "Run to the Hills", which charted at number seven on its release.  It was not until 1983's "Piece of Mind" that the songwriting process became a more varied and collaborative approach, with just four of its nine tracks being credited solely to Harris, two to Dickinson and Smith, one to Harris and Murray, one to Dickinson alone, and one to Harris, Dickinson, and Smith.  The Dickinson and Smith-penned "Flight of Icarus" was the first Iron Maiden single to chart in the United States, reaching number eight on the "Billboard" Mainstream Rock chart. Iron Maiden are a British heavy metal band, founded in 1975 by bassist Steve Harris in London, England.  After several personnel changes in the 1970s, the band settled on a lineup of Harris, Paul Di'Anno (lead vocals), Dave Murray (lead and rhythm guitars), Dennis Stratton (backing vocals, lead and rhythm guitar) and Clive Burr (drums), before they set out on their first professional tour, the Metal for Muthas Tour which supported the compilation album of the same name.  After taking on a supporting slot with Judas Priest on their British Steel Tour and setting out on their own headline tour in support of their debut album, "Iron Maiden", the band supported Kiss on the European leg of their Unmasked Tour, following which Stratton was dismissed because of musical differences.  Guitarist Adrian Smith was hired, following which Iron Maiden set out on a short series of UK dates before recording their second studio album, "Killers". The Iron Maidens: World's Only Female Tribute to Iron Maiden is the debut album by American all-female tribute band The Iron Maidens.  The album features selected tracks originally performed by British heavy metal band Iron Maiden.  Michael Kenney, keyboardist for Iron Maiden, appears as a guest musician on the Japanese import version. "Run to the Hills" is a song by the English heavy metal band Iron Maiden.  It was released as their sixth single and the first from the band's third studio album, "The Number of the Beast" (1982).  Credited solely to the band's bassist, Steve Harris, although significant contributions were made by lead vocalist Bruce Dickinson, it remains one of their most popular songs, with VH1 ranking it No. 27 on their list of the 40 Greatest Metal Songs and No. 14 on their list of the Greatest Hard Rock Songs.
Answer: The Number of the Beast