The Beach Boys' unreleased and bootleg recordings

Many recordings and performances by the Beach Boys have attained some level of public circulation without being available as a legal release, and several albums by the band or its members were fully assembled or near completion, before being shelved, rejected, or revised as an entirely new project.

[1] In 2003, Stylus Magazine named the Beach Boys' Smile, Landlocked, Adult Child, and Dennis Wilson's Bambu "A Lost Album Category Unto Themselves".

Summer's Gone was the original title for the group's 2012 reunion album That's Why God Made the Radio, and an album-length suite was written in the theme.

[12] In the 1990s, Brian worked with multi-instrumentalist Andy Paley on an assortment of recordings destined for a potential album that could have featured some involvement with the Beach Boys.

[22] According to Charles Manson, the musician later convicted for several murders, he took part in "a pretty fair session, putting down about ten songs" at Brian's home studio.

"[24] In Vincent Bugliosi's 1974 book Helter Skelter, he reported that Dennis claimed to have destroyed the tapes, because "the vibrations connected with them don't belong on this earth.

"[25] While the group denied that tapes of these sessions exist – with co-productions by Carl and Brian (not Dennis as had often been stated) – engineer Stephen Desper concurred that they do, believing at the time that Manson's material was "pretty good... he had musical talent.

"[12] The recordings were not demos as is often believed, but complete studio productions of songs which may have later appeared as rerecordings on his album Lie: The Love and Terror Cult (1970).

[30] Of the songs rerecorded, it was only the semi-instrumental "Passing By" that was eventually released on the compilation album Wake the World: The Friends Sessions in 2018, with notable differences being the addition of lyrics sung by Brian.

Cows in the Pasture is an unfinished country and western album by band promoter Fred Vail that was produced by Brian Wilson in April 1970.

Recordings were made for songs entitled "Yeah", "Oh Lord", "City Blues", "I Made a Prayer" or "I Search This World", "Why Don't You Tell Me Why" or "You've Been", and "I Feel So Fine" (including a snippet of a cover of the Ronettes' "Be My Baby") on bootlegs as well as a rendition of "Heroes and Villains" with at least one other song, a ballad entitled "Bobby, Dale and Holly", having yet to surface officially or otherwise.

[34] "I Made a Prayer" was reworked into "This Isn't Love" and recorded by actor Alan Cumming for the 2000 film The Flintstones in Viva Rock Vegas' soundtrack.

Brian later rerecorded "City Blues" (without co-writing credits of Dennis and/or Leon) featuring Eric Clapton for his 2004 album Gettin' In Over My Head.

The name derives from Stephen McParland's book The Wilson Project, drawn from journals and tape diaries kept by Usher from the period.

It was rejected twice by Sire Records due to the inclusion of a rap song entitled "Smart Girls" and certain lyrics written by Wilson's conservator Eugene Landy.

[38] Beginning in 1997, the Luxembourg-based[38] bootleg label Sea of Tunes (named after the Beach Boys' original publishing company) began releasing a series of CDs featuring high-quality outtakes, session tracks and alternate recordings that spanned the group's entire career.