Nat Hentoff has called music writer Peter Guralnick "a national treasure," but a surer measure of Guralnick's skills as biographer and essayist of America's country, rhythm-and-blues and rock 'n' roll legends is his impact on readers. It's hard to imagine reading Guralnick's chapters on the likes of Bobby Bland, Howlin' Wolf or Merle Haggard in his critically acclaimed "Feel Like Going Home" (1971) and "Lost Highway" (1979) without wanting to head for the record store to find the music that had inspired such authoritative yet loving portraits.

Guralnick's latest book, "Sweet Soul Music," focuses on southern soul music, a style that mostly came and went with the '60s. What fascinates Guralnick is not just the wonderful legacy of gospel-based R&B left by Otis Redding, Joe Tex, Wilson Pickett, Sam and Dave and others. Because soul music rose with the civil rights movement and became a galvanizing expression of the realities and aspirations of American blacks, the music's decline in the early '70s has always carried the sense of an unfinished, even failed, cultural episode.

Part of the "Southern dream of freedom" embodied in soul music was integration, or as Otis Redding's brother Rogers puts it, "What made it work, the key to it all, was black and white working together, working as a team." One of the revelations of "Sweet Soul Music" is that although the public face and voices of soul music were black, the studio ensembles of producer, songwriters and musicians for classics like Percy Sledge's "When a Man Loves a Woman," Aretha Franklin's "I Never Loved a Man" or Wilson Pickett's "In the Midnight Hour" were black and white.

Soul music also brought black artists and white audiences together in unexpected ways. Guralnick teases some wonderful stories from his subjects. For some, like Percy Sledge, success was a chance to turn the tables: "At the conclusion of his first tour, he checked into the same hospital in which he had worked as an orderly, ensconced himself in the most expensive room for a week, and let those for whom he had worked wait on him in turn while he suffered from 'nervous exhaustion.' "

In a way, there are two books in "Sweet Soul Music." The first is the six individual chapters devoted to soul's seminal artists -- pioneers Sam Cooke and Ray Charles and Solomon Burke, Otis Redding, James Brown and Aretha Franklin. Like his earlier works, Guralnick's essays on these giants magically transform interview materials, historical scholarship, critical insight and unabashed passion into living, breathing and almost singing portraits.

As good as these individual essays are, the dramatic center of Guralnick's book lies in the three chapters tracing the somewhat improbable rise of Memphis' Stax/Volt labels, the home of Rufus and Carla Thomas, Otis Redding, Booker T & the MGs, Sam and Dave, Isaac Hayes and others. Beginning in a run-down movie theater at the start of the '60s, a few businessmen and a group of talented musicians and artists built first a hit-making label, then the internationally renowned "Memphis sound" and finally a myth.

What is amazing about the Stax story is how casual, uncalculated, even naive its whole record-making operation was. It was not until the Stax-Volt artists headed to Europe for a 1967 tour that most of the artists and musicians even realized how well known their music and names had become. As in many successful businesses, however, Stax's fame inevitably engendered jealousies, money battles and more grandiose business schemes, all of which eroded the subtle creative collaborations that made Stax's soul music so great. By 1975 the company was bankrupt and disco ruled the land.

Guralnick, however, places the collapse of soul music and its dream earlier, in 1967 and 1968, when first Otis Redding and then Martin Luther King died. If there is a flaw to "Sweet Soul Music," it's that Guralnick never really moves past music history to the broader cultural and political action the music was part of. If the "Southern dream of freedom" died, or at least went into exile, he knows that soul music remains to remind us of that dream. Now we have "Sweet Soul Music" to remind us of exactly how soul music came to be, "black and white together, working as a team."

The reviewer writes frequently about pop music for The Washington Post and other publications.