Allen, who is now cancer-free, said that he really began to work on the book in November of 2009 after his first cycle of chemotherapy.
Allen said that writing Idea Man "was very helpful in getting me through chemotherapy because I would struggle to get going every day, and I would start describing things that happened and then eventually when I was toward the end of my chemo and then afterward, I would spend a long time editing and editing and editing. I went through every word in the book eight times."
"My old feeling for the craftsmanship of programming came back," Allen told Wired.com, "and I tried to get everything, the words, the phrases, as best as I could."
Idea Man has generated much discussion in the press because of the candid way Allen describes his relationship with Gates, his boyhood friend and business partner. Most notably, Allen describes how Gates tried to dilute Allen's ownership stake in Microsoft over the course of several years, which led to a rift between the two men, the details of which have never been fully revealed. And he describes Gates' legendary temper and hard-driving management style.
Allen told Wired.com that he did not write the book in order to attack Gates, and he said he's neither bitter nor angry toward his friend. Rather, Allen said, he wanted to tell his own personal story, which includes the history of Microsoft, as he recalls it, while he still has time.
"I wanted to tell the whole story from my perspective, and the ups and downs of our partnership, which was incredibly productive, and then, as the book tells, things slowly changed and I felt like I had to leave Microsoft," Allen said. "I thought people would be interested to know the key moments and the key events, and how things came together and how things ended up dissolving in the end."
"When those events happened there was a real sting and disappointment and surprise and all of those emotions, and I felt very strongly, and then after a period of years, I let it go," Allen continued. He said the dispute with Gates was "the last element in my deciding to finalize my departure from Microsoft, and there was no going back."
I asked him about his relationship with Gates now.
"I consider us friends," Allen said. "We've been through many ups and downs in the past and, you know, these events happened 30-some years ago. At some point, we'll sit down and have an intense discussion about his recollections and my recollections and all that, but this book is meant to be my view of how things happened."
"It's funny to see something like The Social Network come out, and see that shot of Harvard Square in the first few minutes of the movie," Allen continued, chuckling.
"That gave me a certain flashback because that's where I found the magazine," he said, referring to the copy of Popular Mechanics he discovered in 1974 with a picture on the cover of the Altair 8080, the world's first microcomputer. Within one year, Gates had dropped out of Harvard, and the two men had founded Microsoft.
The rest, as they say, is history.