master whose only peers were Jimi Hendrix and Eric Clapton, and Gregg Allman, a tremendously soulful singer, leading the way, the Allman Brothers Band created Southern rock and changed the landscape of American music for hundreds of bands.

But after a year of immense popularity, the group's unique mix fell out of favor as its extended boogies began to meander. Since then, periodic reunions (another of which is shaping up for the summer) haven't offered much more than nostalgia and the occasional serviceable tune.

It's been twenty years since the Allman Brothers' debut album, so it's a sensible (if arbitrary) moment for the reevaluation offered by Dreams, a sprawling, five-hour-plus retrospective (spread across four CDs and cassettes or six LPs) that reclaims the place of the Allmans in the first rank of American bands.

On the surface, proving the worth of the Allmans is an easy task. The band's first four albums, especially At Fillmore East, remain sprightly and inventive. (Compiler Bill Levenson, who also programmed Eric Clapton's Crossroads box, knows these are the best: More than one-third of the tracks come from the 1969-72 heyday.) On the lengthy versions of "I'm Gonna Move to the Outskirts of Town," "Whipping Post" and "In Memory of Elizabeth Reed," Duane and fellow guitarist Dickey Betts sketch out directions that guitar experimenters have frequently retraced. Yet Duane and Betts rarely soared so far away from a song's essence that the solos became ends rather than means: They expanded, but they didn't try to force a song to accept a solo it didn't need.

The finest example of this method is a previously unreleased jam of "You Don't Love Me" and "Soul Serenade" recorded live in 1971. Intended as a tribute to Duane's friend and occasional collaborator King Curtis, the great saxophonist who had recently been murdered, the nineteen-minute medley displays Duane's ability to transform his playing to accommodate a song's changes and his fellow performers' demands. Along with his session work for Derek and the Dominos ("Layla") and Boz Scaggs ("Loan Me a Dime"), this jam stands as one of Duane's finest moments.

There are great, unreleased tracks culled from the nonheyday years surveyed in Dreams, most notably a cover of "Rain," recorded by Gregg with the Charles May Ensemble in 1985, that owes more to Ray Charles than the Beatles. Eve