David Baldacci may be one of the world’s best-selling authors, but he’s a lousy party guest. “I was at a party and somebody went up to my wife and said, ‘Is David ill? He’s just staring at the wall.’ And she glanced over and said, ‘He’s fine, he’s just finishing a chapter.’ If I have an off switch, I haven’t found it.”

Today, Baldacci has consented to leave his work for a while and talk to me over Zoom from his office in Reston, Virginia, although I’m not convinced that one hand isn’t polishing off another novel just out of sight of the camera. The rewards for his dedication to his craft have been ample: he is a regular number one bestseller in both the States and the UK, and worldwide sales of the library of crime novels he has published over the past three decades have passed 150 million copies.

Baldacci, 64, can afford to chuckle at the memory of his first novel, the political thriller Absolute Power (1996), almost going unpublished in Italy on the grounds that his name sounded too Italian and “they’re only interested in crime fiction over there if it’s written by an American”.

He had to publish it in Italy under the pen name “David Ford”, but today everybody knows who he is. A few years ago, he visited the Tuscan town from which his grandfather had emigrated to Virginia: “They held a David Baldacci day, and I was greeted by a marching band and the American flag flying over the village hall for the first time since World War II.”

Baldacci hasn’t achieved this level of success by being chained to his desk. When he began his series about military investigator John Puller in 2011, he put in the research: “I went down to one of the big bases in Georgia, where the Infantry and the Rangers train, and I spent three days down there getting my ass kicked from one end of the base to the other. They put you in this rotating Humvee, so that you’re hanging upside down under this 10-tonne f—er in your full gear. And I achieved something: when it was finished, I got out, and the sergeant who was doing the test said, ‘Sir, that’s the fastest anyone’s ever gotten out of one of those things.’”

The creation of John Puller has led to a fairly one-sided feud between the amiable Baldacci and one of his rivals for the title of King of Crime: Lee Child, who has called Puller “a total bloody rip-off” of his own Jack Reacher. (In Child’s 2013 novel Never Go Back, Reacher tangles with a dim-witted thug called Ronald David Baldacci and ends up breaking his arms.)

“I’ve enjoyed the Reacher books, but John Puller is in the army, he’s a military investigator who travels with other agents and investigates crime, he’s in uniform and abides by the rules of the army. Reacher is ex-army, more of a vigilante who goes to some town and takes out a lot of bad guys.”

“I just write my stuff and Lee writes his, and I wish him all the best. I’ve never really publicly commented about some of the stuff he said just because I thought it was unworthy even to discuss. I have never bad-mouthed any writer, ever, in public, because not enough people read books as it is – why would I try to divide us and not unite us?”

Baldacci’s latest novel – by my count his 54th, not including several children’s books – sees the return of another of his regular heroes, ex-Army Ranger turned Homeland Security fixer Travis Devine, whose adventures are in the process of being adapted as a series of films for Netflix. The new book, To Die For, sees Devine placed in loco parentis for a spiky 12-year-old girl whose parents have apparently died of drug overdoses, and is Baldacci’s response to the opioid crisis. “We’re losing 100,000 citizens a year to fentanyl overdoses, and I’m trying to address the reasons for it, but you can arrive at your own conclusions about what should be done about it. I’ve frankly got on my soapbox in other books, but I’ve got better about doing that. My job is not to write a polemic, it’s to tell a story.”

Thought-provoking as it may be, To Die For is also a high-body-count adrenalin-pumper that takes Devine to a small rural town still taking its political inspiration from the Ku Klux Klan. “There are still these isolated enclaves around the country where people who would like to see a far different America than what we have today would like to take the country back in time.”

Baldacci says he “grew up in the Sixties in the middle of Jim Crow in the South with racists all around me, and a lot of them are still racist to this day. But what saved me were books: my parents took us to the library. Books teach you how to empathize with people you don’t know much about.”

With a mechanic father and a mother who worked for a telephone company, Baldacci “grew up very blue-collar with – I know this sounds cliché-ish – not a whole lot of money but a whole lot of love.” He went on to study law and practiced for nine years in Washington DC. Most of his novels convey a fairly jaundiced view of the US justice system. “Justice in America really depends on how much money you have and the lawyer that you can hire. That’s why there are no millionaires on death row.”

Clint Eastwood doesn’t like what he’s hearing in Absolute Power (1997), based on Baldacci’s novel of the same name.

During his years as a lawyer, he was writing every night from 10pm to 3am. He spent three years on Absolute Power, a thriller about the US president’s involvement in his lover’s violent death, as accidentally witnessed by a burglar: it secured him $4 million for US and foreign rights, plus a further $1 million for the movie rights. Within a year, Clint Eastwood had produced, directed and starred in the film, although after that dream start he had “a long drought with Hollywood”. Over the past 18 months, however, “a dam burst: now I’m having so many Zooms with film and TV companies sometimes I can’t remember which series I’m talking about, which is a nice problem to have.”

In addition to his major indulgence – collecting first editions of the great American authors – Baldacci ploughs a lot of his money into the foundation he has set up with his wife Michelle. As well as providing funding for libraries, colleges and literacy programs, he is backing an outfit called “the Centre for Civic Dialogue, which aims to bring people together to discuss things rationally and civilly, without the hostility and histrionics of so much online discussion. If I could wave a magic wand, I would banish all social media from this earth.”

Although he won’t formally enter politics himself, he devotes much of his time to political causes, and he and fellow thriller writer Michael Connelly are helping to pay for a new office in Florida for PEN America to focus on the battle against the growing movement to ban controversial books in schools.

“I’ve had death threats because of some of my books”, he says, notably for suggesting in his 2005 novel The Camel Club, written in the aftermath of the invasion of Iraq, that “we can’t denigrate people just because of the religion they practice and that war’s not always the answer. I had to hand some of those over to the FBI.”

But, he adds, “I’m proud at least to have challenged what some people think. These parents who say, Oh God, we can’t let our kids read anything that would make them uncomfortable. That’s what books are supposed to do! What do you want to do: eat vanilla every day of your life, or read something that challenges you?”

Jake Kerridge writes about books for The Telegraph