English rock band Led Zeppelin's untitled fourth album, commonly known as Led Zeppelin IV, was released on 8 November 1971 by Atlantic Records. Produced by guitarist Jimmy Page, it was recorded between November 1970 and January 1971 at several locations, most prominently the Victorian house Headley Grange. After the band's previous album Led Zeppelin III received lukewarm reviews from critics, they decided their fourth album would officially be untitled. This, along with the inner sleeve's design featuring four symbols that represented each band member, led to the album being referred to variously as , Four Symbols, The Fourth Album, Untitled, Runes, The Hermit, and ZoSo (which was derived from Page's symbol).

After the lukewarm, if not confused and sometimes dismissive, critical reaction Led Zeppelin III had received in late 1970, Page decided that the next Led Zeppelin album would not have a title, but would instead feature four hand-drawn symbols on the inner sleeve and record label, each one chosen by the band member it represents. "We decided that on the fourth album, we would deliberately play down the group name, and there wouldn't be any information whatsoever on the outer jacket," Page explained. "Names, titles and things like that do not mean a thing."  Page has also stated that the decision to release the album without any written information on the album sleeve was contrary to strong advice given to him by a press agent, who said that after a year's absence from both records and touring, the move would be akin to "professional suicide." In Page's words: "We just happened to have a lot of faith in what we were doing." In an interview he gave to The Times in 2010, he elaborated:  It wasn't easy. The record company were sort of insisting that the name go on it. There were eyes looking towards heaven if you like. It was hinted it was professional suicide to go out with an album with no title. The reality of it was that we'd had so many dour reviews to our albums along the way. At the time each came out it was difficult sometimes for the reviewers to come to terms with what was on there, without an immediate point of reference to the previous album. But the ethic of the band was very much summing up where we were collectively at that point in time. An untitled album struck me as the best answer to all the critics -- because we knew the way that the music was being received both by sales and attendance at concerts.  Releasing the album without an official title has made it difficult to consistently identify. While most commonly called Led Zeppelin IV, Atlantic Records catalogues have used the names Four Symbols and The Fourth Album. It has also been referred to as ZoSo (which Page's symbol appears to spell), Untitled and Runes. Page frequently refers to the album in interviews as "the fourth album" and "Led Zeppelin IV", and Plant thinks of it as "the fourth album, that's it". Not only does the album have no title, but there is no text anywhere on the front or back cover, or even a catalogue number on the spine (at least, on the original vinyl LP release).

How many songs were on the fourth album?