Eminem has revealed details of his long-awaited new album, "Relapse," in an exclusive interview with Billboard, conducted via email. The set is due next spring from Shady/Interscope.

Eminem is working on "Relapse" with longtime collaborator Dr. Dre, who put his own album, "Detox," on the backburner to help bring the project to completion.

"Me and Dre are back in the lab like the old days, man," Eminem says. "Just him banging away on tracks and me getting that little spark that makes me write to it. I don't have chemistry like that with anyone else as far as producers go -- not even close. Dre will end up producing the majority of the tracks on Relapse.' We are up to our old mischievous ways ... let's just leave it at that."

A handful of songs intended for "Relapse" have leaked online, most recently "Crack a Bottle," leaving Eminem "really heated. It wasn't close to finished, and it even has me doing guide vocals for Dre as a suggestion of how he could lay his verses down. It's like someone catches you peeping in your window before you got the Spider Man costume all zipped up! Nobody is supposed to see that. We are gonna finish it up though and get it out there how it's supposed to be."

Eminem also responded to producer Swizz Beats' recent comment that he'd submitted a track for the project described as a sequel to the hit single "Stan," telling Billboard, "I haven't worked with Swizz on this album.

"There isn't a 'Stan 2,' and there won't be," he says. "Stan drove his car off a bridge and I'm not writing a song as Stan's ghost. That would just be really corny."

While working on "Relapse," Eminem was also writing his autobiography, "The Way I Am," with Sacha Jenkins. The book has received favorable reviews and has spent time in the top 20 of the New York Times hardcover nonfiction best-sellers list.

"For me, writing an album is an entirely different process from making this book," he says. "The album requires a certain focus of mine that I can't really explain -- let's just say it's all I can really do while I'm doing it. With the book, the process was much more spread out, like, 'Let's get you together with Sacha for a few hours next week. Let's go thru these photos and artwork, etc.' The book was a lot more of a focus here-and-there thing as opposed to music, which totally consumes me every second."
 
Eminem goes into great detail in "The Way I Am" about how much he was impacted by the 2006 shooting death of fellow Detroit rapper Proof, who was one of his best friends.

"Opening the book with Proof's chapter was real important for me," Eminem says. "Everything from my past moving into my future is marked by his passing. It's sort of like life when Proof was with us, and life after -- a real dividing factor. He means more to me than a book chapter could describe, but I'm glad I was able to put him first, like he did for me so many times."
 
As for Shady Records' 2009 roster, Eminem says 50 Cent's delayed "Before I Self Destruct" will be out in February. "He's still working on it and getting back together with me and Dre next week to finish up," he says. "I have a couple of tracks on there with him. It's sick."

Afterward, Ca$his will release the follow-up to his 2007 "County Hound EP." Says Eminem, "People are going to be surprised what he is capable of. I produced a bunch of records on there as well."