"One is from George W Bush and he stays on the right wall, and the other is from Bill Clinton, and his letter is on the left wall," he says, laughing. "The streams never cross. In the late 1990s, Clinton picked one of my books as his favourite work of fiction of the year. It was around the time that he was testifying in the Monica Lewinsky affair, and people were making fun of the fact he had gone out and bought The Simple Truth. They said he might be able to use some of that in his testimony."
When I meet David, he is on a whirlwind trip to Dublin with his wife Michelle to promote his thriller, The Sixth Man, the fifth in the highly acclaimed series featuring private investigators Sean King and Michelle Maxwell. He has written 16 novels, is published in 80 countries, and has sold almost 70 million books.
Clint Eastwood produced, directed and starred in the film version of his debut novel Absolute Power, and David and his wife run a literacy charity in the US called Wish You Well, which is dedicated to supporting literacy efforts across America.
Given the subject matter of his books, his work requires huge research, and he has great access to the Pentagon and the world of intelligence and crime-fighting for it. He is also in demand all around the world for book-related events -- which, he says, is his biggest challenge. His wife Michelle also finds that it makes a lot of demands on his time.
"David is very loyal and you can always count on him," she says. "He can be very, very focused on his work, so sometimes he has to be reminded that he has a family and there are other things going on in the world than work. This has been a very busy year for our family, as our daughter is going away to college in the fall, and David has taken on way too many projects at the same time."
David, the youngest of three children, went to law school and spent 10 years as a trial lawyer. He jokes that some of the best fiction he ever wrote was when he was a lawyer. Michelle travelled around the States as a child as her dad was in the navy, and while she hated it then, she says it was a wonderful experience in retrospect.
The eldest of three children, she trained as a paralegal, and met David at a vegetarian barbecue in 1988, although neither is veggie. He says he was immediately intrigued by her, although she wasn't interested at first, as she spent her days surrounded by lawyers.
"I was a young lawyer and very arrogant, cocky and sure of myself," recalls David. "I was telling people about cases I'd handled when I felt a tap on my shoulder. Michelle said that she had heard I was a lawyer, so I asked her if she wanted to hear some of my cases, but she said no. She said, 'I wouldn't go around telling people that you're a lawyer if I were you,' and once she had insulted me, I knew I had to date her."
So, it was a case of "treat them mean" then? "Yeah, she slapped me around a little bit so I had to come back for more," he jokes. "I worked up the courage to call her and ask her out, but I felt like I was back in high school. We were going out for lunch, and I brought 10 neckties in to work and asked a female colleague to help me pick out the best one."
Michelle says that while she thought David was a "bit full of himself", he was also "very cute" -- and had pre-season football tickets. They found that they had a lot in common with their backgrounds, both coming from parents who were very hard-working. They shared a similar sense of humour, which they say has been very important, especially after 21 years of marriage, two teenage children -- daughter Spencer and son Collin (Michelle's maiden name) -- and two dogs, Guinness and Finnegan.
"It's a good thing it has gone by fast," says David. "There haven't been too many times when we thought about faking our own deaths. It's a lot of work, but it's also a lot of fun."
David was 34 when he became a published author and Absolute Power took him three years to write. Prior to that, he wrote short stories and screenplays. He now writes two books per year, although for many years it was just one. His biggest thrill was the first time he saw his book for sale on the shelf.
"It was nice of David to become a writer, since I didn't like lawyers," says Michelle. "When he left law in 1995, it was a mutual decision for us. He had sold one book, but we had no idea if he was going to sell another book or how well they'd sell."
David says that while Michelle is his biggest support, she has mellowed over the years and keeps everything going at home. While she jokes that she is "very demanding", she prefers to stay at home while he is travelling, although she loves to come on special trips with him, such as the one to Dublin.
"She must have a bit of Irish in her, because she has a temper," he says. "She really takes care of everything and is very nurturing in that regard, but she's very tough. She has her rules and expectations about the way she likes people to behave. Our kids are great -- they're very respectful and polite and nice, and it wasn't by happenstance. Kids need discipline and structure and rules, and Michelle provides all of those things, and it shows me that she really cares about other people."
The Sixth Man (Pan Macmillan, €13.99) by David Baldacci is out now. Visit www.wishyouwell foundation.org for more details about the Baldaccis' literacy charity in the US