There is a moment in “Mystery Train” when the author, Greil Marcus — the preeminent writer on the connections between music and American culture — pauses, looks around in bewilderment, and wonders why critics have never written about Jimi Hendrix’s “Little Wing” with the same intensity and passion as they have fawned over Dylan or the Beatles. It is, to be sure, a curious omission in rock ’n’ roll’s accumulated literature, as few other songs display such a brilliance, such a wonderful malleability.

Jimi Hendrix was probably the finest guitarist of the 1960s, and “Little Wing” counts among his masterworks. That quick pickup at the very outset of the song and the subsequent deeply soulful notes and chords, reverberating and undulating in their own captivating way, are almost indescribable in their beauty and softly transfixing power. With Hendrix’s tender singing, “Little Wing” is a love song, yes, but only nominally; it sounds more like a rumination on the six-stringed instrument itself. With its odd two-and-a-half minute brevity, the song is an experiment, as Hendrix probes the outer bounds of his medium. Like many of the Beatles’ early singles — or the entire album “Revolver” — “Little Wing” has the feel of a quick, preliminary sketch, which Hendrix barely has time to scratch down before shaking his head and deciding to scrap it and move on. Hendrix, evidently, didn’t grasp the song’s enormous potential; instead he allowed it to remain unpolished, leaving later guitarists to retread and build upon the path he had laid.

Eric Clapton was the first of those later guitarists. Three years after the release of “Little Wing,” he decided to remake Hendrix’s original with Derek and the Dominos, the band he led at the time. The result was a six-minute epic almost unsurpassed in its extraterrestrial ambition. Whereas Hendrix starts with a smooth groove, Clapton makes his guitar into a trumpet, and begins the song with a stately fanfare, the sharpness of which threatens to puncture the atmosphere. Then the wondrous lead guitar breaks through, marvelous, ethereal, almost otherworldly in its stark clarity. In its vast reach, it rises above the other instrumentation and floats like a piece of burning paper, transcending the constraints of gravity. The vocals — split between Clapton and keyboardist Bobby Whitlock — are harsh and raw, but as the two singers stretch their ranges, their voices begin to shimmer with a certain brightness. The strangely surreal lyrics, meanwhile, approach incomprehensibility, except for one phrase, haunting in its simplicity: “fly on, little wing.” But soon this proves sadly ephemeral, as that majestic guitar overwhelms all else and drifts towards another dimension. “CLAPTON IS GOD,” proclaimed graffiti on the London Underground in the early 1960s. That, in short, is “Little Wing” — Clapton’s guitar, aspiring to apotheosis.

Then there’s Stevie Ray Vaughan’s version. Before his untimely demise in a helicopter crash — far, far too many Southern rock guitarists died in transportation-related accidents — he too made “Little Wing” his own. He reduced the song to nothing more than guitar, bass and drums: no singing and little studio production. But this liberates the song rather than limiting it; whereas Clapton’s guitar soared ever higher, Stevie Ray’s sounds resolutely and comfortably grounded. His six-minute version, twice the length of Hendrix’s, has the same soulfulness, but far more feeling. With his uncanny ability to coax the entire emotional spectrum out of those six strings, Stevie Ray needed no vocals.  At one moment he’s quiet, diminutive, strumming his way along, but then suddenly he explodes into a cacophony of sound, the guitar snarling and sneering, until he’s back in that irresistible groove, where the guitar’s tone rings with a velvety richness. Look no further for a masterpiece of pathos and technical skill: it’s all here, the pride and the joy, the pain and the devastation. Stevie Ray may have better tracks — “Voodoo Child” is a reasonable candidate — but “Little Wing” demonstrates the full extent of his remarkable abilities.

Both Clapton’s and Stevie Ray’s versions certainly seem “better” than Hendrix’s original. The later guitarists succeed because they take Hendrix’s skeletal fragment and imbue it with a new meaning and new life. It takes a particular genius to reinvent the works of another, a certain ambition and confidence — arrogance, perhaps, to think that you might elevate the work of a master to an even higher level. The best songs invite the best covers. Think of “Hallelujah,” a track which, when Jeff Buckley sang it, sounded like a biblical revelation, entirely foreign from Leonard Cohen’s original; think of “Thunder Road,” a song that assumes a new identity every time Bruce Springsteen performs its grand drama on stage; think of “I Shall Be Released,” a tale of confinement and escape that becomes something unique each time a new performer takes it up. The greatest songs must be malleable — they must never sound the same twice and they must offer the tantalizing hope of total reinvention. That is the power and the glory of “Little Wing”: that such a fragmentary palimpsest of a song could give rise to some of the greatest guitar playing ever heard, albeit in the hands of those who had no role in its original creation. And so “Little Wing” shall never perish, for, just as each generation writes its own version of history, each artist can play a fresh version of Hendrix’s masterwork.