Updated

Bitter? Who's bitter?

Definitely not Microsoft co-founder Paul Allen, despite comments in his new book that seem critical of Bill Gates success. Allen defends his book in an upcoming episode of "60 Minutes," telling host Lesley Stahl the comments were meant to depict a slice of history -- and not as revenge.

Allen, who left Microsoft in 1983, wanted to tell that history the way it happened, he says in the show this Sunday. In a video excerpt CBS posted on its website, Allen says he hopes people understand this.

“It’s not about [revenge]. I just felt it was like an important part of technology history and I should tell it like it happened,” says Allen.  “I hope people understand and respect that,” he tells Stahl.

He also says the book’s timing should not blunt the high-profile charity work Gates has been doing. “The timing had nothing to do with the many wonderful things Bill has done…the timing was because I wanted to see if I could do it and hopefully be alive to see it published,” says Allen, who was writing the book in 2009 while under treatment for Stage 4 lymphoma.

More On This...

For all the harsh pictures he paints of Gates, Allen reveals another side, too. Gates, who now focuses on philanthropy, comforted Allen when he got cancer a second time in 2009. Says Allen: "there's a bond there that can't be denied."

Allen's book, "Idea Man," hits shelves Tuesday. The "60 Minutes" episode airs Sunday.