Aqualung is the fourth studio album by the English rock band Jethro Tull; it was released in March 1971 by Chrysalis Records. Though it is generally regarded as a concept album, featuring a central theme of "the distinction between religion and God", the band have said there was no intention to make a concept album, and that only a few songs have a unifying theme. Aqualung's success signalled a turning point in the career of the band, who went on to become a major radio and touring act.

Recorded at Island Records' new recording studio in Basing Street, London, it was their first album with keyboardist John Evan as a full-time member, their first with new bassist Jeffrey Hammond, and last album featuring Clive Bunker on drums, who left the band shortly after the release of the album. The album utilises more acoustic material than previous releases; and—inspired by photographs of homeless people on the Thames Embankment taken by singer Ian Anderson's wife Jennie Franks—contains a number of recurring themes, addressing religion along with Anderson's own personal experiences.

Aqualung is Jethro Tull's best-selling album, selling more than seven million units worldwide. It was generally well-received critically and has been included on several music magazine best-of lists. The album spawned two singles, "Hymn 43" and "Locomotive Breath".

"My God" was recorded on 11–12 April 1970, followed by "Wond'ring Aloud" on 21 June, both at Morgan Studios. After an American tour, bass player Glenn Cornick was fired from the band, and was replaced with Jeffrey Hammond, an old friend of Ian Anderson. Aqualung would be Hammond's first album with the band. It would also mark the first time John Evan had recorded a full album with the band, as his only prior involvement was to provide several keyboard parts on the previous 1970 album, Benefit. In December, the album became one of the first to be recorded at Island Records' newly-opened recording studios on Basing Street in London. Led Zeppelin did some recording for Led Zeppelin IV at the same time, though in the smaller of the two studios in the converted chapel. In an interview on the 25th anniversary edition of the album, Tull's bandleader Ian Anderson said that trying to record in the larger studio was very difficult, because of its "horrible, cold, echoey" feel. The orchestral segments were arranged by Dee Palmer, who had worked with the band since 1968's This Was, and would later join as a keyboard player. The master reels were assembled at Apple Studios on 2 March 1971. Aqualung would be the last Jethro Tull album to include Clive Bunker as a band member, as he retired shortly after recording to start a family.

The songs on the album encompass a variety of musical genres, with elements of folk, blues, psychedelia, and hard rock. The "riff-heavy" nature of tracks such as "Locomotive Breath", "Hymn 43" and "Wind Up" is regarded as a factor in the band's increased success after the release of the album, with Jethro Tull becoming "a major arena act" and a "fixture on FM radio" according to AllMusic. In a stylistic departure from Jethro Tull's earlier albums, many of Aqualung's songs are acoustic. "Cheap Day Return", "Wond'ring Aloud" and "Slipstream" are short, completely acoustic "bridges", and "Mother Goose" is also mostly acoustic. Anderson claims his main inspirations for writing the album were Roy Harper and Bert Jansch.

Aqualung has generally been regarded as a concept album with a central theme of "the distinction between religion and God". The album's "dour musings on faith and religion" have marked it as "one of the most cerebral albums ever to reach millions of rock listeners". Academic discussions of the nature of concept albums have frequently listed Aqualung amongst their number.

The initial idea for the album was sparked by some photographs that Anderson's wife Jennie took of homeless people on the Thames Embankment. The appearance of one man in particular caught the interest of the couple, who together wrote the title song "Aqualung". The first side of the LP, titled Aqualung, contains several character sketches, including the character of the title track, and the schoolgirl prostitute Cross-Eyed Mary, as well as two autobiographical tracks, including "Cheap Day Return", written by Anderson after a visit to his critically ill father.

The second side, titled My God, contains three tracks—"My God," "Hymn 43" and "Wind-Up"—that address religion in an introspective, and sometimes irreverent, manner. However, despite the names given to the album's two sides and their related subject matter, Anderson has consistently maintained that Aqualung is not a "concept album". A 2005 interview included on Aqualung Live gives Anderson's thoughts on the matter:

I always said at the time that this is not a concept album; this is just an album of varied songs of varied instrumentation and intensity in which three or four are the kind of keynote pieces for the album but it doesn't make it a concept album. In my mind when it came to writing the next album, Thick as a Brick, was done very much in the sense of: 'Whuh, if they thought Aqualung was a concept album, Oh! Okay, we'll show you a concept album.' And it was done as a kind of spoof, a send-up, of the concept album genre. ... But Aqualung itself, in my mind was never a concept album. Just a bunch of songs.

Drummer Clive Bunker believes that the record's perception as a concept album is a case of "Chinese whispers", explaining "you play the record to a couple of Americans, tell them that there's a lyrical theme loosely linking a few songs, and then notice the figure of the Aqualung character on the cover, and suddenly the word is out that Jethro Tull have done a concept album".

The thematic elements Jethro Tull explored on the album—those of the effects of urbanisation on nature, and of the effects of social constructs such as religion on society—would be developed further on most of the band's subsequent releases. Ian Anderson's frustration over the album's labelling as a concept album directly led to the creation of Thick as a Brick (1972), intended to be a deliberately "over the top" concept album in response.

"Lick Your Fingers Clean" was recorded for Aqualung, but was not included on the album. The song was drastically re-worked as "Two Fingers" for Tull's 1974 album, War Child. "Lick Your Fingers Clean" was eventually released in 1988 on the 20 Years of Jethro Tull collection. It was then released as a bonus track on the 1996 and 2011 reissues of Aqualung.

Another song, "Wond'ring Again" was recorded on 21 June 1970 together with the original version of "Wond'ring Aloud" (included as one single seven-minute song on the Steven Wilson remaster of associated recordings 1970–1971, titled "Wond'ring Aloud, Again"), and was considered for release on the album before Anderson decided to drop it from the final track listing. "Wond'ring Again" was subsequently released on the compilation album, Living in the Past, in 1972. A re-recording of "Wond'ring Aloud" was included on Aqualung. Glenn Cornick played bass on the song and says it is his favourite song he recorded with the band. Cornick also played bass on early studio recordings of "My God" and "a couple of other songs", though he did not say which they were.

The album's original cover art by Burton Silverman features a watercolour portrait of a long-haired, bearded man in shabby clothes. The idea for the cover came from a photograph Anderson's wife took of a homeless man on Thames Embankment, and Anderson later felt it would have been better to have used the photograph rather than commission the painting. Ian Anderson recalls posing for a photograph for the painting, though Silverman claims it was a self-portrait.

The artwork was commissioned and purchased by Chrysalis Records head Terry Ellis in 1971. Silverman was paid a flat fee of $1,500 for the painting. There was no written contract. The artist says the art was only licensed for use as an album cover, and not for merchandising; he approached the band seeking remuneration for the additional uses, such as printing it on T-shirts and coffee mugs.

The original artwork for both the front and back covers are missing. They were apparently stolen from a London hotel room, or perhaps from Chrysalis' office during a robbery. The original artwork for the interior gatefold painting was not taken during the robbery and is held by Terry Ellis.

In April 1971, Aqualung peaked at number four on the UK Album Chart; when the CD version was released in 1996, it reached number 52. It peaked at No. 7 on the Billboard' North American pop albums chart; the single "Hymn 43" hit No. 91 on the Billboard Hot 100 chart. The album would go on to sell over seven million copies, and is the band's best-selling album. Aqualung was one of Jethro Tull's albums that were released in quadraphonic sound. The quadraphonic version of "Wind Up", which is in a slightly higher key, is included on a later CD reissue of the album as "Wind Up (quad version)".

The single "Hymn 43" was released on 14 August 1971, and reached number 91 on the Billboard Hot 100 charts, spending two weeks in the chart. The song was the first single to chart by the band in the United States. It was later included in the video game Rock Band 2 as downloadable content; which also featured the album's title track.

The album was re-released in a 40th anniversary edition on 31 October 2011. The release contains a new stereo and 5.1 surround remix of the album by British musician and producer Steven Wilson, the original quadraphonic mix, and comes in three different editions—a "collector's edition" containing the album on LP and two CDs, as well a DVD and a Blu-ray disc (with better sound quality than the DVD) and a hardback book; a "special edition" containing the two CDs and an abridged version of the book; and an "adapted edition" containing two CDs (with 2 extra songs not included in the other two 40th anniversary editions) and 2 DVDs in a hardcover book (written content is the same as in the Collector's Edition book, only the Chronology differs slightly). Justifying the remix, Steven Wilson said: "Jethro Tull's Aqualung is ... a masterpiece, but was sonically a very poor-sounding record. So, some didn't rate it as highly as they should have. What we did with Aqualung was really make that record gleam in a way it never gleamed before. I think a lot of people, including myself, have come around to thinking that the album is a lot better than they even gave it credit for previously. So, there is certainly something very gratifying about being able to polish what was already a diamond and making it shine in a way it never has before". Additionally, according to mastering engineer Steve Hoffman there were tape stretching problems with the original session mixdown master, implying that many editions of the album used multigeneration copies as their source.

Professional ratings

Review scores
Source	Rating
AllMusic
Christgau's Record Guide	C+
The Daily Vault	A
The Encyclopedia of Popular Music
MusicHound Rock	4/5
PopMatters	10/10
Record Collector
The Rolling Stone Album Guide
Zagat Survey Music Guide - 1,000 Top Albums of All Time

Aqualung received mixed to favourable reviews from contemporary music critics. Rolling Stone magazine's Ben Gerson lauded its "fine musicianship", calling it "serious and intelligent", although he felt that the album's seriousness "undermined" its quality. Sounds said that its "taste and variety" made it the band's "finest" work. Aqualung was voted the 22nd best album of 1971 in The Village Voice's annual Pazz & Jop critics' poll. Robert Christgau, the poll's creator, was more critical of the album in a 1981 review, and described Anderson's undeveloped cultural interests and negative views on religion and human behaviour as both boring and pretentious.

In retrospective reviews the album is generally lauded and viewed as a classic. AllMusic's Bruce Eder called Aqualung "a bold statement" and "extremely profound". In a review of the album's 40th anniversary re-release, Sean Murphy of PopMatters said that Aqualung "is, to be certain, a cornerstone of the then-nascent prog-rock canon, but it did—and does—exist wholly on its own terms as a great rock album, period". Murphy also praised the additional material featured on the release, finding that the new content was "where a great album gets even better". Paul Stump's History of Progressive Rock was more measured in its praise, saying that Aqualung made little advancement over the group's previous album, Benefit. He identified the improvements as the deeper, wider arrangements, and the diversions of the melody from the bassline accompaniments. He found the side two song cycle rambling but added that "if the lyrics were now tending towards the provocatively obscure, they were none the less possessed of some style, not least in their Blakean allusions". Steve Harris, the bass player for the heavy metal band Iron Maiden, has called Aqualung "a classic album", lauding its "fantastic playing, fantastic songs, attitude [and] vibe". Iron Maiden would go on to cover "Cross-Eyed Mary" as the B-side of their 1983 single "The Trooper".

Aqualung has also been appraised highly in retrospective listings, compiled by music writers and magazines. Martin Barre's solo on the album's title track was included in Guitarist magazine's list of "The 20 Greatest Guitar Solos of All Time" at number 20.

Publication	Country	Accolade	Year	Rank
The Village Voice	US	The 1971 Pazz & Jop Critics Poll	1972	22
Classic Rock	UK	The 100 Greatest Rock Albums of All Time	2001	30
Rolling Stone	US	500 Greatest Albums of All Time	2012	337
The 100 Best-Selling Albums of the 70s	UK		2004	90
Q	UK	40 Cosmic Rock Albums	2005	7
1001 Albums You Must Hear Before You Die	US		2005	No order
Guitarist	UK	The 20 Greatest Guitar Solos of All Time	2011	20
Prog	UK	The 100 Greatest Prog Albums of All Time	2014	43

Original North American Reprise Records pressings of Aqualung contained a slightly edited version of the title song, with its first three seconds (i.e., the first repetition of the song's signature riff) removed. These pressings correspondingly list the song's length at 6:31.

The 2011 version was remixed by Steven Wilson and remastered by Peter Mew.

CD 1: Original Album

The 2016 edition was remastered by Steven Wilson of his 2011 remixed material as he did not like Peter Mew's mastering.

Aqualung Live is a live album of a performance of Aqualung before an audience of 40 invited guests at XM Studios in Washington, D.C., on 23 November 2004. It was released in the UK in September 2005 by RandM Records. In the US, the album was given away to ticket holders on almost all US concerts in October and November 2005, before being given an official release on 7 March 2006. Royalties from the European release went to various charities for the homeless.

Track listing

All songs written by Ian Anderson

1. "Aqualung" – 7:56
2. "Cross-Eyed Mary" – 4:34
3. "Cheap Day Return" – 1:21
4. "Mother Goose" – 5:39
5. "Wond'ring Aloud" – 2:00
6. "Up to Me" – 3:35
7. "My God" – 8:27
8. "Hymn 43" – 4:22
9. "Slipstream" – 0:59
10. "Locomotive Breath" – 5:19
11. "Wind-Up" – 6:40
12. Riffs – Another Monkey – 1:27
13. Recording the Original – 2:05
14. Choosing My Words with Care – 1:17
15. Hummmmmm 43 – 0:35
16. A Different Kettle of Very Different Fish – 1:02
17. But is It Any Good? – 1:42

• Ian Anderson – lead vocals, acoustic guitar, flute, production
• Martin Barre – electric guitar, descant recorder
• Jeffrey Hammond (as "Jeffrey Hammond-Hammond") – bass guitar, alto recorder, odd voices; backing vocals on "Mother Goose"
• John Evan – piano, organ, Mellotron
• Clive Bunker – drums and percussion

Additional personnel

• Glenn Cornick – bass guitar (played with the band at rehearsals for the album in June 1970, some of which may also have been recording sessions – particularly early versions of "My God" and "Wondring Again/Wondring Aloud" – although he is not credited on the album)
• John Burns – recording engineer
• Dee Palmer – orchestral arrangements and conducting
• Burton Silverman – album artwork
• Terry Ellis – producer

Chart (1971)	Peak position
Australian Albums (Kent Music Report)	3
Canada Top Albums/CDs (RPM)	5
Danish Albums (Tracklisten)	3
Finnish Albums (The Official Finnish Charts)	6
German Albums (Offizielle Top 100)	5
Italian Albums (Musica e Dischi)	2
Norwegian Albums (VG-lista)	3
UK Albums (OCC)	4
US Billboard 200	7

Chart (1996-1997)	Peak position
German Albums (Offizielle Top 100)	44
UK Albums (OCC)	53
UK Rock & Metal Albums (OCC)	6

Chart (2016)	Peak position
Austrian Albums (Ö3 Austria)	60
Italian Albums (FIMI)	42
Scottish Albums (OCC)	37
Spanish Albums (PROMUSICAE)	89
UK Albums (OCC)	76
UK Rock & Metal Albums (OCC)	2

Region	Certification	Certified units/sales
Germany (BVMI)	Gold	250,000
United Kingdom (BPI) 2011 release	Gold	100,000
United States (RIAA)	3× Platinum	3,000,000
Shipments figures based on certification alone.

• Aqualung (album) at Discogs