A year -- nearly to the day -- after Epic released the single-disc Number Ones compilation in November 2003, the long-awaited Michael Jackson box set finally saw the light of day. Entitled The Ultimate Collection, the 57-track set spans five discs -- four CDs and one DVD containing a live show in Bucharest shot on the Dangerous tour -- and runs his entire career, from the Jackson 5's early hits for Motown to Invincible in 2001. It's the first set to cover so much ground, which is eye opening. To hear Jackson evolve from the exuberant kid singing "I Want You Back" and "ABC" to the young adult behind the vibrant disco of "Shake Your Body (Down to the Ground)" and "Don't Stop 'Til You Get Enough" is exciting and instructive; even if you're familiar with this material, it's different to hear the music change over the course of one disc. Unfortunately, The Ultimate Collection doesn't contain too many more revelations (although the early, radically different version of "P.Y.T. (Pretty Young Thing)" is not only revelatory -- it's practically a different song -- it's also musically noteworthy). Since Jackson has had such a long career filled with so many hits, there are too many hits to fit into the four discs, and not all of them are nearly as invigorating or ageless as much of the music that comprises the first two CDs. These are the discs that are devoted to the Jackson 5, the Jacksons, and Michael's solo career through Thriller, and with only a few exceptions -- such as the ludicrous "Thriller" itself -- the music still sounds terrific. The set starts to downshift on the third disc, when Jackson's career started to wind into second gear, at least creatively. This covers Bad, a spotty but still effective gloss on Thriller that had several good singles, along with Dangerous, a similarly uneven record. Which leaves the fourth disc to chronicle Jackson's muddled '90s and 2000s, selecting hits and album tracks from the commercial disappointments HIStory -- the album of original songs included on that two-CD set, not the hits collection -- and Invincible. Throughout the four discs, there are a bunch of rarities scattered about, ranging from demos (including the original "We Are the World" featuring only Michael's vocals) and remixes to unreleased songs, selections from The Wiz, the Jacksons' duet with Mick Jagger on "State of Shock," "Someone in the Dark" from the hard-to-find ET's Storybook, the ridiculously stilted Captain EO theme "We Are Here to Change the World" (its production seems better suited for The Adventures of Buckaroo Banzai than a Disney sci-fi flick), and "Someone Put Your Hand Out," an exclusive Pepsi-supported cassingle from the Dangerous tour. Some of this stuff is quite good -- "Sunset Driver" from 1982 and "Cheater" from 1987 are so funky, loose, and alive that it's hard not to wish that Jackson didn't fuss over his albums and just record like this all the time -- but a lot of this illustrates Michael's taste for MOR schlock (such as the children's tale "Scared of the Moon," a tie-in with his 1984 book of the same name). Since that schlock starts to surface halfway through disc two, it bogs down the set -- not enough to completely hurt it, but enough to make this pretty much the province of the hardcore fans, who will delight in the number and variety of rarities here (which is the primary attraction of the set, since the DVD is merely OK and the book is skimpy, offering only a Nelson George essay and a time line, along with many photos, most of which look fairly familiar). For the less dedicated, this is just a shade short of being definitive. It may be easy to carp about what's missing on any box set, but fans looking either for a concentrated dose of Michael at his best -- which would have been the Jackson 5 up through and including parts of Dangerous -- or a collection of all of his hits will find this somewhat unsatisfactory (for the record, the following hits are all absent on this set: "The Love You Save," "Never Can Say Goodbye," "Rockin' Robin," "Human Nature," "Say Say Say," "Another Part of Me," "Leave Me Alone," "In the Closet," "Will You Be There," "Scream," "This Time Around," "They Don't Care About Us," "Heaven Can Wait," "One More Chance"). Despite these problems, The Ultimate Collection comes close enough to getting it right to qualify as a successful box set.