With the five-disc 40th Anniversary Super Deluxe Edition of 1973's 'Goodbye Yellow Brick Road,' Elton John has managed to expand what was already his biggest musical treasure trove.

The eight-times platinum 'Goodbye' marked the peak, and approximate midway point, of John's amazingly prolific string of best-selling '70s albums. Unlike peers who seemingly intended to make grand artistic statements with their double albums around that time (or Led Zeppelin, who, incredibly, were just trying to clear out a backlog of unreleased tracks for 1975's 'Physical Graffiti'), John, his band and songwriting partner Bernie Taupin apparently wandered into an especially hot creative streak, coming up with the album's 18 tracks in short order.

The songs on 'Goodbye Yellow Brick Road' cover a lot of territory, from the distorted guitar attack of 'Saturday Night's Alright for Fighting' to the stately, melancholy 'Goodbye Yellow Brick Road,' gorgeous ballads like 'Harmony and 'Candle in the Wind' and the progressive rock synths of the opening 'Funeral for a Friend / Love Lies Bleeding.' (Boy, how cool would it be if he just stayed in outer space for a whole album like that one?)

The album rates just a notch below A+ two-LP classics like 'Exile on Main Street' and 'Electric Ladyland,' as there are a couple of less-than-amazing tracks to be found in the middle -- particularly 'Jamaica Jerk-Off,' a cloying and quickly tiresome attempt at reggae. But considering the fact that the nearly equally amazing album 'Caribou' followed this one by just eight months, these rare missteps are easily forgiven.

This admirably compact box set version of the album features a hardback book filled with fantastic photographs and essays from and about the album recording sessions and the tour that followed, and two CDs worth of a surprisingly muscular 1973 concert. There's also a documentary named 'Say Goodbye Norma Jean and Other Things' that chronicles the creation of the album as well as Elton's humorous attempts to balance the modest and showy aspects of his personality -- talking about the lack of sincerity in the music business while being interviewed on camera in the middle of a bubble bath, for instance.

A fifth disc features b-sides from the album sessions, stand-alone singles from around the same era, a handful of demo versions and nine largely pointless covers of the album's big hits by contemporary stars like the Zac Brown Band and the Band Perry. But those obvious marketing concessions are easily ignored, and the 40th Anniversary Editon of 'Goodbye Yellow Brick Road' remains a fantastic way to learn more about this already very impressive album.