ATLANTA, Georgia (CNN) -- Sam Cooke knew exactly what he wanted.He wanted to sing, and he did it beautifully. He wanted to be famous, and he shrewdly took opportunities, rising from local gospel star to nationally known crooner to pioneering soul man. He started his own label, SAR Records, ran his own publishing and kept pushing forward.He wanted to be in control of his destiny, and he was -- until he let part of himself get out of control on a grim night in December 1964, shot to death at a two-bit Los Angeles hotel.His drive was the stuff of legend. Observers sometimes wondered -- with the singing, the business, the women (lots of women), the sheer motion -- when he slept.Because even as a child, Cooke had his eye on big things."You know, sometimes I think he thought he was the smartest person in the world," his brother, L.C. Cook (Sam added the "e" many years later), tells author Peter Guralnick in Guralnick's exhaustive new Cooke biography, "Dream Boogie" (Little, Brown)."He believed he could do everything until the day he died," says Guralnick, relaxing on a couch in an Atlanta hotel.And yet, Guralnick acknowledges, for someone so accomplished Cooke was a hard man to know.Despite talking with family members, business partners, peers and prot�g�s -- Guralnick's hundreds of interviews included Specialty Records founder Art Rupe, manager Allen Klein, friend and partner J.W. Alexander, Cooke's siblings and the singer's wife, Barbara -- there was something about Cooke he couldn't quite get at."For someone so gregarious and charming, he was at heart an introspective, private person," the author says. "After I spoke to a couple hundred people, I realized that there was not a single person whose life he hadn't touched, not simply as an example but as a mentor. And yet, as true as those stories were -- and there were an infinite number -- they were all from the outside."'Full dimensions'What comes from the inside, he adds, is in the music. That's what attracted Guralnick, author of the acclaimed Elvis Presley biographies "Last Train to Memphis" and "Careless Love," to his subject in the first place."The gospel music put me over," he says. "Specifically hearing 'Live at the Shrine' ['The Great 1955 Shrine Concert'] in which he sings 'Nearer to Thee.' That just destroyed me. It made me see the full dimensions of Sam Cooke."Cooke was born in 1931, in Clarksdale, Mississippi (the same Clarksdale famous for its bluesmen and crossroads soul-selling), but raised in Chicago, Illinois, the son of a preacher man. He was a studious child and read voraciously, but he also had a voice -- a powerful, angelic instrument that caused men to sit up and women to swoon.But Cooke, as his records make clear, was no belter. He carried his audiences with a whisper, not a scream; with easy, sensual moves, not James Brown splits.His songs were conversational, casual and -- particularly in the early solo years -- gossamer, sometimes to the point of novelty ("Everybody Loves to Cha Cha Cha").Cooke had a knack for the effortless hook, the simple story. Guralnick describes the singer writing "Touch the Hem of His Garment," a hit for Cooke's mid-'50s gospel group, the Soul Stirrers. The Stirrers were riding in a car with producer Bumps Blackwell on the way to a recording session and had little material."So Sam said, 'Well, hand me the Bible,' " Blackwell recalls in "Dream Boogie." "And they handed Sam the Bible, and he was thumbing through it, skipping over it and skimming through it, and he said, 'I got one. Here it is right here.' " At which point, Guralnick continues, Cooke wrote the song on the spot.'Something's going to happen' Peter Guralnick worked on his Sam Cooke biography for almost 15 years -- and had it in his mind for many more.His songs, performed hopefully -- even downbeat tunes such as "Sad Mood" and "Chain Gang" -- often belie the conditions of Cooke's working life. As a black man, he was segregated from hotels, restaurants and concert venues -- particularly in a Jim Crow South just awakening to the civil rights movement, which forms a parallel story in Guralnick's book.Cooke also wanted to appeal to the widest possible audience, and it wasn't until well into his solo career that he made a conscious effort to add gospel flavorings to his pop releases, particularly the call-and-response of "Bring It On Home to Me.""When he went pop, he consciously bleached out the sound with 'You Send Me' [and others]. It was not accidental," Guralnick says.But Cooke was always growing, perhaps most notably in one of his most stunning songs (and greatest performances), "A Change Is Gonna Come." The song "just came to me," Cooke once recalled, and it electrified others with its bold lyrics and passionate melody.It also scared him; the song seemed to have rushed to life from his most vulnerable places."That really bothered him -- where it came from -- and also, he was afraid he had gone beyond his audience," Guralnick says. (Cooke held off on recording the song for months; it wasn't released until after his death.) "He knew it was a song he had to record, but he said he was never going to sing it [live]." (He did, but not much.)His friend Bobby Womack felt something else, an ominousness. "It feels eerie, like something's going to happen," he told Cooke.Guralnick shrugs off Womack's darker premonitions, but there's no question the song, at once elegiac and defiant, seems to represent a turning point. "It's highly suggestive in various ways," Guralnick says. Besides being one of Cooke's most personal songs, it became a theme of the civil rights movement.By the time he wrote "Change," Cooke was starting to feel some strain. He had big ideas for his future -- he was starting to develop inner-city talent in Los Angeles -- yet he was struggling with emotional scars: His only son had died in a drowning accident in June 1963, and his often-rocky marriage to Barbara was falling apart. Cooke was drinking more and becoming increasingly rootless.It culminated in that night in December 1964, when Cooke went to the Hacienda Hotel with a strange woman and ended up dead, shot by the hotel manager. Guralnick presents the story as plainly as possible, though mysteries remain: Cooke's behavior, what happened to a large bankroll he was assumed to carry around, inconsistencies with testimony. The answers, nearly 41 years later, are likely unknowable.Much like Sam Cooke himself, a man apart.Guralnick says that even his closest colleagues still talk about him with a sense of respect. "They looked up to him. Even Barbara -- she's still trying to understand Sam. And J.W. -- Sam was the person he'd liked to have been."Because, while he was alive, Cooke lived every moment to the fullest."I don't even know why I do what I do," he told Bobby Womack. "When I do it, it just comes."