Author Matt McGee reveals how he compiled the book in this interview and shares some of his findings from “U2 — A Diary.”

You assembled much of the material for this book through your blog, with fans helping out with research and information and photos. When you established the blog, did you envision a book would come out of it?

Matt McGee: Well, the book actually came before the blog. I had been chatting with the publisher, Omnibus Press, for a while about doing “U2 — A Diary.” As soon as it became pretty obvious that we were going to go ahead with the book, I registered the domain and started planning how I wanted to use the blog to support the book — the researching, writing, promotion and everything related to it. And now that the book is published, I can also use it to invite readers to send in any extra information they have about what’s in the book, or events and facts that I may have overlooked.

What were some things you learned from their input that you didn’t know about the band before beginning this project?

MM: The fans were really great about helping out. Whenever I’d put out a call for help, I always had replies from fans — sometimes within an hour or two, sometimes a day or two. And they were helping with some very detailed questions. For example, I knew that [U2 drummer] Larry [Mullen] had marched in an anti-war rally in Dublin in 2003 but had no idea when. As soon as I asked, a couple fans dug up the exact date for me. Another example would be the date of the video shoot that Bono did with Frank Sinatra for “I’ve Got You (Under My Skin).” I had one source saying that happened in October 1993, but after asking on the blog, fans pointed me toward more reliable info with the exact date: Nov. 5, 1993. They also helped iron out a lot of inconsistencies with early concert dates and things like that.

There are some key stories in the band’s history that you tackle in this book. Let’s take on a couple of them. What happened during Bono’s visit to Central America in 1986 that helped shape The Joshua Tree?

MM: Two songs specifically came from that trip: “Bullet the Blue Sky” and “Mothers of the Disappeared.”

But, to me, what’s really interesting about it is the timing. I didn’t know that Bono and [his wife] Ali arrived in Central America immediately after spending several days in New Zealand at the funeral of Greg Carroll, Bono’s personal assistant, who had died in a motorcycle accident in Dublin. His death had devastated the whole U2 organization, but especially Bono and Ali — they were very close to Carroll. So, with that in mind, you get a better sense of the mental and emotional state they were in when they arrived in Central America and spent almost two weeks there.

What did you find was the major reason for the difficulty U2 had in recording the Pop album?

MM: I think they pretty much lost their sense of identity, and their sense of direction. There’s a quote in the book where Bono says the band “went out a lot” while they were trying to record Pop, that they spent a lot of time out on the town — “living it large” is the phrase Bono uses. They’ve always been a band that absorbs the things around them, but I think in this case they went overboard. And then, making it worse, Universal/Polygram was desperate for the record to come out in time to save their 1996 financials. It was very tense. In the book, Marc Marot, an Island Records guy since the 1980s who was part of Universal/Polygram, says he was “under enormous pressure from above to get the record out.” But, he couldn’t force U2 to do it without ruining his longtime friendship with them.

What did you find out with regard to the creation of Zoo TV?

MM: Willie Williams — U2’s longtime tour and lighting diector — tells a great story about how every tour begins with a phone call, just him and Bono, that lasts for hours. In this case, as Willie tells the story, Bono wants Willie to join them on the island of Tenerife, where they’re going to see the carnival. Bono tells Willie that the band is making the “most exciting record of their career,” and that it demands an extraordinary live show. Bono also says he has this phrase in his head — “Zoo TV” — and “an absurd pair of oversized sunglasses, which he felt were important, too.” It’s a great story, told only as Willie Williams can tell it.

You go all the way back to the 1950s Dublin when Bono’s parents were married. What did you find out about his home life?

MM: The thing that stands out to me is that Bono’s sense of justice — what we see so much now in his humanitarian work — started when he just a little kid. There’s a story in the book that Bono has told about his first day of school. He’s four years old. He apparently watched two kids fighting, and one kid bit the other kid’s ear. So Bono grabbed the kid who did the ear-biting and slammed his head into an iron railing. In a sense, he’s been doing that kind of thing ever since, trying to right what he sees as wrongs.

As far as your research goes, when was it that U2 realized they were going to be big? What were there ambitions starting out?

MM: Being big was the plan all along. It’s why they were a perfect fit for Paul McGuinness. He had opportunities to manage other bands but wanted a young, enthusiastic band that he could groom for worldwide success. And there’s a quote from Edge in the book where he says that U2 “didn’t want to be a cult group, we wanted to be a big group,” and that’s why they pursued McGuinness as their manager in the early days. Beyond that, there’s the famous quote from 1980 where Bono says “we are meant to be one of the great groups.” This showed up in U2’s first mention in Rolling Stone. Talk about ambition!

How has U2 been able to stay together for so long?

MM: I’m not sure they can even explain it. But it seems to me that, like a good marriage, they started out as friends first. And for all the things they have in common, they’re also four very unique individuals with different personalities. Like, if anyone other than Bono had his flair and love of the limelight, they’d probably have imploded long ago. And I also think they’re smart enough to realize that what they have together is better than what any of them would have on their own.

Do they work in much the same way they did when they began, or has their celebrity caused changes in how they interact in the studio or on the road?

MM: The biggest change in recent years has obviously been Bono’s activism. There are some mentions in the book about the strain that caused during the recording of All That You Can’t Leave Behind. He spent a lot of time away from the studio in 1999 and 2000 when the rest of the band was making music. And I think part of the strain was that a lot of Bono’s humanitarian stuff — the appearances, speeches, etc. — was being organized out of the band’s Dublin headquarters. And as I mention in the book, when Bono formed DATA in 2002, that burden finally shifted away from Principle Management. Now, all of that stuff is separate from U2. DATA/ONE is a fully functioning organization, Bono has an agent that handles speaking requests, and so forth. I think it frees them up to work together as a band when they are together.

Why did you choose to use a diary format for the book?

MM: I would love to claim the idea as mine, but it wasn’t. In 2005, I was pitching an idea for a different U2-related book. Omnibus Press was high on my list, because of their experience in publishing U2 books. When I pitched them on my idea, they weren’t interested — but they did have an idea to tell U2’s story in a diary format. Omnibus had already published an excellent diary-style book about The Beatles, and felt U2 would be a good subject for a book in that same format. I’ve always been a U2 historian, so I jumped at the chance to write “U2 — A Diary.”

Do you have a lot of material left over, maybe enough for another book?

MM: Everything I was able to confirm and attach to a date is in the book. Every fact, story, appearance and so forth; nothing was held back. But, there’s a small collection of stories, events and other things that I was never able to confirm to my satisfaction, so those are not in the book. If we ever do an update of “U2 — A Diary,” hopefully I’ll be able to get some of those mysteries solved.