The guitar great has been working on Rocks: My Life in and Out of Aerosmith for over four years, but didn't want to release the tome for fear it would simply serve as an "answer" to biographies written by drummer Joey Kramer and Steven Tyler.
He tells Rolling Stone, "It's finally done. We're just finishing up taking the pictures and going through all the little details that go with it.
"I've wanted to write one (book) for a while, but Joey put his book out (2009's Hit Hard: A Story of Hitting Rock Bottom at the Top) and I wanted to leave some room there, and then Steven put his book out (2011's Does the Noise in My Head Bother You?). I didn't want to make it seem like mine was an answer to his, so I waited a little longer."
Perry admits that, like Tyler, he has been brutally honest in the book and he fears that may lead to problems when it is released in October (14).
He adds, "It's a good thing it comes out after the tour. That kind of guarantees we'll finish up the tour, no matter what anybody thinks about the book."
But he insists there's big differences between his memoir and his singer's 2011 tome, stating, "He's allowed to perceive things how he perceives things. He can write his book any way he wants. But I didn't agree with a lot of the things he said. I know he worked hard on it, but it's got a totally different tenor and energy than my book.
"Mine tends to be a little more traditional. It's an autobiography in the real classic sense. I just hope Steven accepts the things I say about how I felt and how I saw things happen. I don't put words in other people's mouths or talk about conversations that I wasn't there for."