EVEN great artists don't release every piece of music they record, which is a good thing - we don't need to hear every demo, take or misfire they've ever committed to tape or hard drive because, let's face it, even great artists have off days.It's becoming more common for these forgotten tunes and/or albums to see the light of day. Nirvana's With The Lights Out box set revealed some grungey gems amid Kurt Cobain's dodgy boombox sketches, while the deluxe two-disc versions of Jeff Buckley's Grace and Live At Sine have some magic that deserves to be heard.But in honour of the many lost masterpieces, unfinished symphonies and hidden hits still out there, Musicology has compiled this list of the greatest music you've never heard... part one.Smile - The Beach BoysTHE most mythical of lost masterpieces is this attempted follow-up to their ground-breaking Pet Sounds. Partially recorded, the project ceased in early 1967 for a number of reasons - bandleader Brian Wilson's increasing insanity, unrest within the band, record label pressure, and drugs (mostly taken by Wilson). Bootlegs of some tracks circulated for many years and some surfaced on the rush-job release Smiley Smile, while a five-disc set Good Vibrations - 30 Years of the Beach Boys released in 1988 revealed about 30 minutes of material intended for Smile, showing the band was closer to finishing the album than many realised. Wilson and collaborator/lyricist Van Dyke Parks revisited the project in 2004, releasing new recordings of an updated version, but the unfinished '60s attempt remains the biggest 'what if?' in pop music.Carnival Of The Light - The BeatlesTHE Beatles cleaned out their closet with the mid-'90s Anthology series, which failed to uncover any major masterpieces, but was lapped up by Fab Four fans all the same. Very little worthy material remains in the archives of the greatest band of all time, but Beatles' lovers are still keen to hear this unreleased 14-minute-long psychedelic piece of nonsense. Recorded in 1967 for an art event, it apparently features detuned drums and organs sounds, distorted guitar, sound effects, random yelling and no discernible tune. In recent times Paul McCartney has hinted at releasing it for the hell of it, although he would need permission from Ringo Starr, Yoko Ono and Olivia Harrison to do so. The only other unreleased Beatles material remaining is some White Album demos, the hundreds of bits and pieces and whole songs recorded during the Let It Be sessions and the mythical tape of The Beatles jamming with Elvis (which possibly doesn't even exist but is something of a musical holy grail for rock buffs).Chrome Dreams/Homegrown - Neil YoungONE website lists nine unreleased Neil Young albums but the two best known ones were recorded during his prolific mid-'70s period. Chrome Dreams (1977) and Homegrown (1975) were both shelved in favour of other albums (American Stars 'N' Bars and Tonight's The Night respectively). Many of the songs from these two records ended up on other albums either in original form or re-recorded, including the two previously mentioned plus Zuma, Hawks & Doves, Freedom and his era compilation Decade. An acetate of Chrome Dreams surfaced in the '90s, showing just how close Young was to releasing it. Despite never putting the album out, he did unveil Chrome Dreams II in 2007, however Young fans are still desperate to see properly released versions of both albums, which only exist in partial bootlegs at the moment.PrinceACCORDING to our calculations there are roughly a dozen unreleased Prince albums, not counting live records and EPs. Even his rarity compilations The Vault: Old Friends 4 Sale and the five-disc Crystal Ball barely scratched the surface. Crystal Ball was originally the name of a three-LP set that was trimmed to the two-disc Sign Of The Times, and a Crystal Ball II, with a further 17 unreleased tracks, was planned but never saw the light of day. Then there's side project The Rebels, live jam album The Flesh, the almost-finished Camille project, a double-LP called Dream Factory, a third album by his jazz-fusion group Madhouse and a few more that haven't been released. Talk about prolific - few artists have as much released stuff, let alone unreleased music.Pink FloydONE of the most bootlegged bands in history, Pink Floyd has at least 30 unreleased songs - some of which may or may not exist in recorded form. They date from the band's first pieces during the Syd Barrett days such as Lucy Leave and Butterfly through to Peace Be With You from the band's penultimate album A Momentary Lapse Of Reason (their first record without bassist/dictator Waters). Ironically, Peace Be With You was written by guitarist David Gilmour as a friendly farewell to Waters but it never saw release due to the acrimonious lawsuits that began flying back and forth between Waters and the remaining Floyds.