McCartney in 1964. At the time, his musical primacy was taken for granted. Photograph from RA / Lebrecht Music & Arts

Every historical inquiry has a saturation point, past which new inquiry becomes simply old inquiry repackaged, and, on that principle, it seems that we may at last have reached peak Beatles. (As we long ago reached peak Churchill-in-the-war and peak van Gogh-in-Arles.) What’s to know is known. Certainly this is the case with Philip Norman’s new life of Paul McCartney, called, simply, “Paul McCartney: The Life.” A reader familiar with the past twenty years of Beatles biography will have a pretty hard time finding a single new fact or revelation within its pages. The closest thing is the discovery, already hinted at in the first volume of Mark Lewisohn’s multivolume Beatles life, “Tune In,” that the day John met Paul—July 6, 1957, for those outside the faith—was not actually the first time Paul met John. Paul had, it seems, observed him several times before, as an intimidating “teddy boy” (a kind of dandyish hoodlum) on the local bus. Within the narrow world of Beatles iconomania, where that day has been realized on film at least twice, and has even been the subject of a lengthy book, this is news, though not very big news, since the premonition only adds to the accepted meaning of the meeting: scary, hyper-mature, and aggressive John meets sweet (though sexually precocious) Paul, and something happens.

The absence of news isn’t really an indictment of Norman’s energy or purposefulness as a biographer. After Lewisohn; after Barry Miles’s strange “Many Years from Now,” a semi-official biography; after Albert Goldman’s “The Lives of John Lennon” and the Beatles Anthology series, there just isn’t much left to say. Even if there were something left to say about McCartney’s life in the forty-six-year period since the Beatles’ breakup, the crucial seven years that make the rest matter are by now almost too well documented. Lewisohn’s “The Beatles: Day by Day,” back in 1990, supplied a nearly hourly account of what happened to the four boys when they were famous and together.

And yet, even though we’re drowning in Beatle fact, something mysterious remains, and that mysterious thing, as always in the lives of artists, is how they did what they did. There is something fated about the Beatles. The first photograph of them in their final fourness, with Ringo on drums, was taken on August 22, 1962; the last was taken exactly seven years later, on August 22, 1969. The space between was filled with music. The notorious 1962 Decca tryout tape, where they failed the audition, and deserved to, seems almost impossible to reconcile with the final, elegiac side of “Abbey Road,” or with the music of the last rooftop concert, in London in January, 1969—all that passionate, smoky, supple playing and singing. The seven years are still almost unbelievable in the growth they evidence. The Beatles were an O.K. provincial rhythm-and-blues group, then they were masters, and they departed having made only masterpieces. How and why it happened—and why, having come so far so quickly, they broke apart so soon—remains the biographer’s puzzle.

The mystery won’t be solved in Norman’s pages, but we’ll be reminded of it. And this biography serves another purpose: it is, essentially, biography as apology. Norman admits that in his earlier books, including a biography of the Beatles called “Shout!” (a weird title, given that the Beatles never recorded and only rarely played that song, and given that shouting is what they didn’t do), he accepted the cheap stereotype of Paul as a self-centered trivialist. Now he sees that Paul was not only a man of genius but also someone who has, past seventy, handled the madness of mega-fame about as well as anyone ever has. Elvis Presley and Michael Jackson died of something very much like suicide; John Lennon was murdered—hardly his fault—but after a long period of withdrawal. Paul is a grandfather and a father, by all accounts a good one, who made a bad rebound marriage after losing a much loved wife, but who has otherwise spent the past twenty-five or so years doing the good work of entertaining countless people and accepting innumerable awards. It’s a nice life to look at. He still strolls the streets of New York, smiling and dismayingly normal. So, if there are no new facts, there is a new attitude: all is forgiven.

As Norman shows, McCartney has worked so hard at seeming an ordinary bloke that it is easy to miss the least ordinary and least bloke-ish thing about him: the magnitude of his melodic gift. A genius for melody is a strange, surprisingly isolated talent, and doesn’t have much to do with a broader musical gift for composition; Mozart certainly had it, Beethoven not so much. Irving Berlin could barely play the piano and when he did it was only in a single key (F-sharp major: all the black keys), and yet he wrote hundreds of haunting tunes; André Previn, who could do anything musically as a pianist and a conductor, wrote scarcely a single memorable melody, although he did write several shows and many songs. McCartney, as Norman reminds us, had the gift in absurd abundance. Before he was twenty, he had written three standard songs—“I’ll Follow the Sun,” “When I’m Sixty-Four,” and what became “Michelle.” By the time he was thirty, he had written so many that he now seems to lose track sometimes, reviving old tunes in concert that he has half forgotten.

Someone could get a Ph.D. thesis out of studying the major-minor shifts in his Beatles songs: sometimes the change is from verse to chorus, to mark a change from affirmation to melancholy, as in “The Fool on the Hill”; sometimes it’s in the middle of a phrase, as in “Penny Lane,” to capture a mood of mixed sun and showers. These are things that trained composers do by rote; McCartney did them by feel—like Irving Berlin writing for Fred Astaire, he was a rare thing, a naturally sophisticated intuitive. Lennon’s tragic martyrdom, and McCartney’s fall from critical favor, made it seem as though one had been regarded as a more consequential figure than the other. In truth, throughout the nineteen-sixties Paul’s musical primacy was largely taken for granted. In 1966, the critic Kenneth Tynan, a hard man to please, proposed doing a profile of Paul, in preference to John, because he was “by far the most interesting of the Beatles and certainly the musical genius of the group.”

Of all the Beatles’ biographical conundrums, the most baffling is their breakup. One minute they were represented, in “Yellow Submarine,” as four Edwardian children inhabiting a magical shared space; the next they were in the midst of squabbles so bitter that they had hardly healed when, ten years later, John was murdered. “Musical differences, business differences, personal differences” was McCartney’s own laconic formula, offered when he released the first post-Beatles album, in April of 1970. The business differences may have been the biggest of all, and they are nicely illuminated by another good recent Beatle book, Fred Goodman’s “Allen Klein: The Man Who Bailed Out the Beatles, Made the Stones, and Transformed Rock & Roll.”

Klein emerges as a marginally more sympathetic figure than earlier Beatles biographies would suggest. The story told in the past is that Klein, a Brill Building shark who had previously managed Bobby Vinton and Sam Cooke, came to London in search of new prey. Having landed the Rolling Stones as a sort of trial munch, he went after the Beatles. John Lennon hired him, wanting, as Klein put it, to have “a real shark—someone to keep the other sharks away.” (Dolphins tell themselves things like this all the time, with predictable results.)