Fred Schruers always thought everything would work out fine -- even when he was embroiled in one of publishing's weirdest deals.

The veteran journalist turned out to be right. His proof arrives Tuesday, when his book, "Billy Joel: The Definitive Biography" (Crown Archetype), reaches stores, more than six years after he started trying to tell the story of Joel's life.

"I always felt something would come of it," says Schruers, discussing the project publicly for the first time. "I felt there might be a happy ending someday."

Of course, for a long time, he may have been the only one who thought that way.

Schruers, who had worked for Entertainment Weekly and Rolling Stone, was the writer Joel hired in 2008 to work on his autobiography, known as "The Book of Joel," for HarperCollins. It was expected to be a bestseller for the publisher, with a planned first run of 250,000 copies and a seven-figure advance for Joel.

However, in March 2011, only weeks before the planned publication date, Joel canceled the book's release. "It took working on writing a book to make me realize that I'm not all that interested in talking about the past, and that the best expression of my life and its ups and downs has been and remains my music," Joel said in a statement.

Months later, he would tell Newsday, "I saw it being promoted as a salacious tell-all, which it wasn't in the first place. I said, 'No, no, no, no, that's not how I want to be defined. Forget it.' I'm not Keith Richards. . . . I'm just not a kiss-and-tell kind of guy."

That's something Schruers knew. He says he always knew it was possible Joel would drop the project. Before Joel pulled the plug on his autobiography, he called Schruers to let him know. "He made me OK with it because he was very candid about it all," Schruers recalls. "I had to give him the right to live his life as he saw fit.

"It would probably be a better story if I threw myself to the ground, tore my clothes and sobbed," Schruers continues, laughing. "But I just said, 'Well, dang. I better move on.' "

And that reaction may be the surest sign of why Schruers and Joel worked so well together. Throughout "Billy Joel: The Definitive Biography," Schruers documents Joel having similar reactions. Whenever the Hicksville native encounters a tough situation, he just keeps moving forward, whether it's business struggles, marital problems or issues with alcohol.

Schruers says it was perhaps that desire to move forward that made Joel uneasy about releasing his autobiography. Joel declined to comment about the new book.

It was only after a chance meeting with Joel in late 2012 that Schruers began work on the new book. "It was sort of a handshake agreement," he says, adding that Joel said he could use all the material he had gathered for the autobiography for the new book. " 'I'll help you out' was his phrase. . . . In Billy's case, that was certainly true.

"I don't think he hated what we had done together," Schruers adds. "But when your dad dies and you're going through a divorce, you're in hip pain and you're pretty emotionally battered, it's not something you want to talk about all the time in interviews. You want more of a peak moment to put that book out."

"Billy Joel: The Definitive Biography" is a much different book, Schruers says. "A biography and an autobiography are further apart than I think we generally reckon," he says, adding that Joel is incredibly well read and knows the difference. "He has a great understanding of what biographies are about, and he has a real respect intellectually for the importance of a biography that was done an arm's length from him."

Schruers says the biography allowed him to put events in a better context by using others' recollections -- something he could not do in "The Book of Joel," which was written in the first person.

That goes for good things (the way Joel's longtime friend and lighting designer Steve Cohen, who also produced a documentary about "The Last Play at Shea," offers behind-the-scenes insights about the historic concerts) and bad (the way FBI agent Tim Crino outlines the case against Joel's former manager Frank Weber). Schruers was able to use all the secondary interviews he did with Joel's inner circle for years, as well as the 100-plus hours of interviews he did with Joel as they toured the world.

Schruers says he flew to Australia to meet with Joel without really knowing whether he had been hired for the project or not, adding, "That was a pretty long flight to take if it turned out I wasn't. . . . But he was the soundtrack to my life."

A few days into the tour, though, it was clear that they clicked. "When we were in our fourth sushi bar in the fifth city, I think I realized that we were really doing this," Schruers says.

They met for months with no set agenda. "It was really free-flowing," Schruers says. "I was following the music and we would talk about songs and what inspired them. . . . The organization comes later."

When they would reach a difficult topic, Schruers says he would still use the music as a jumping-off point. "Everyone who knows him well will say he has a lot of forgiveness in him," he says. "He's got a graciousness about people in his life. If I were searching for bad stuff about so-and-so, he's probably not going to come up with bad stuff about so-and-so. He's going to have a more enlightened, evolved take on those things."

It makes Joel an incredibly rare interview subject, says Schruers, who is currently looking for his next project, though he does have a completed manuscript about The Kinks sitting in a drawer. "You don't always get somebody who is that articulate, who has lived so much, who is willing to have it all trotted out," he says.

Schruers says for most people, especially those on Long Island who have met Joel, "Billy Joel: The Definitive Biography" will offer some new insights, but also will confirm what they already know.

"There's a reason he's the prototypical Long Islander and he's very well loved," Schruers says. "I don't think the public really wants to know the bad stuff, though it's in there. They have their imaginings about Billy, and some of them are reflected by the reality. He's had his bumps. It's very hard to say this without sounding too Pollyannaish, but he really is that good guy that everyone wants him to be."