On June 17 1967, Otis Redding closed out Saturday night at the Monterey Festival with a performance that defiantly broached the colour line in American popular music and turned on the “love crowd”, as he addressed them, to black soul. It was his greatest and his last major appearance on a music stage. Less than six months later, he was pulled dead from Lake Monona in Wisconsin. He had been en route to a less glamorous date at the Factory nightclub, a joint frequented by university students, many of whom would have been turned on to his grown-up and unfashionably hard-edged style by the Monterey coverage.

Just three days before taking off for Madison in his Beechcraft H18 – which joins Patsy Cline's Piper Comanche, Buddy Holly's Beechcraft Bonanza and Lynyrd Skynyrd's Convair C-300 in popular music's aerial necrology – Redding had recorded a song no one else much liked and he maybe had some doubts about, but which circumstance turned into America's first posthumous No 1.

Nowadays, (Sittin' On) The Dock Of The Bay is the song most associated with him, a melancholy tale that brought a new poppy sophistication to the work of an artist whose album career had begun in more familiar blues/r'n'b/soul vein with Pain In My Heart, just a short half-decade before. Redding's white manager Phil Walden didn't much like the song. His wife Zelma Atwood Redding didn't much like the song. Co-writer Steve Cropper noted that Redding had failed to deliver a little ad lib rap at the end and replaced it with a whistled chorus. Stax, on whose Volt imprint (Sittin' On) The Dock Of The Bay was released, had doubts about its demographic even after Monterey, and wanted to dub in a gospel chorus by the Staples Singers.

Nobody who has surrendered to its two minutes of sombre magic has ever been able to imagine it performed any differently. Of the bizarre phalanx of latter-day stars who attempted to cover it – everyone from Sammy Hagar to Justin Timberlake – none has made much sense of its lyric, and the most honest and effective musical memorial remains Jim Morrison's “Poor Otis, dead and gone . . .” intro to Running Blue recorded by The Doors in 1969.

By then, the brief promise of racial harmony, if not integration, had gone under the wheels of riot and assassination. A profound version of Change Is Gonna Come notwithstanding, Redding is rarely cited as an observer on cultural politics in America. But nor is he in the hedonistic line of Little Richard and James Brown, who share (only professionally in Brown's case) a Macon, Georgia, background. And yet Redding was involved in controversy right at the beginning of his career when Shout Bamalama and Fat Gal, neither of which were particularly subtle lyrically, were released on Confederate Records, an imprint that used the infamous (infamous right up to this month) 'Stars and Bars' flag as its emblem. The NAACP objected and black music stations decided not to play the records. In America change is painfully slow to come.

Circumstance dictated that Redding's influence was to be posthumous and overwhelmingly controlled by others. His widow Zelma has retained much of the personal archive rather than depositing it where it might be accessible to researchers. The Redding story is thus inevitably a mixture of oral biography, fan-based reaction and pure mythology.

Mark Ribowsky has written an excellent book, but this isn't it. A previous work on boxing commentator Howard Cosell is also about a man, a myth and the “transformation” of American sports but there the mixture of flowery characterisation and laconic social commentary works fine. Likewise, Ribowsky's excellent study of baseball pitching legend Satchel Paige, a model sports book with a nicely inflected understanding of the racial politics of the diamond game.

Dreams To Remember leans heavily on a demonised model of the music industry that ranks creative artists on the one side against promoters, managers (Phil Walden excepted) and recording executives on the other. Ribowsky even uses such terms as “lice” and “moth” of industry figures.

He represents Redding as an adult performer, turning out in crisp suits and with normal, unprocessed hair, always seeming older than the 26 years he squeezed in; but Ribowsky runs out of ways to verbalise the sheer impact of his performances. Oral accounts confirm that in contrast to the playful infantilism of Little Richard, Jackie Wilson and Little Willie John, Redding traded on a maturity that was not overtly sexual; even Marvin Gaye flip-flopped between social activism and an X-rated bedroom manner, and Gaye's duets with female stars, in sharp contrast to Redding's King & Queen with Carla Thomas, always contained a patronising element.

Three minutes of YouTube archive, and particularly the Monterey footage, give a clearer sense of Redding's presence and musical alertness than any amount of laudatory or analytical prose. “Avatar of the newest soul assimilation”, “pyrotechnics”, “massively significant icon” all find Ribowsky reaching for a comfortable place between cultural studies and fanzine.

Pop's deathcult dictated that (Sittin' On) The Dock Of The Bay would remain laden with non-musical significance. Perhaps Redding's most significant record was his astonishing revival of Try A Little Tenderness. And while you're on YouTube, check out the moment in Jim Cartwright's scouring 1987 play Road, the television version, when Otis's voice and that seemingly overcooked old song song combine to transform Lancashire grime and Thatcher-era hopelessness with something universal and very nearly grand: "You drink. You listen to Otis. You get to the bottom of things." "What for?" "To keep from going mad."

Dreams To Remember: Otis Redding, Stax Records And The Transformation Of Southern Soul by Mark Ribowsky is published by Liveright, £17.99