When British novelist Lee Child lost his job as “presentation director” at Granada Television in 1995, he sat down and wrote a thriller “to keep a roof over my head.” It starred a West Point graduate and former Army MP named Jack Reacher, a nomad who roams America making a living as a “problem-solver.”

That first book, The Killing Floor, began a 22-title franchise that has been translated into more than 40 languages and has sold more than 100 million copies globally. Tom Cruise played Reacher in two movies, Jack Reacher (2012, from the 2005 novel One Shot) and Never Go Back (2016).

Reacher has returned in The Midnight Line, which publisher Delacorte Press describes this way: “Reacher takes a stroll through a small Wisconsin town and sees a class ring in a pawn shop window: West Point 2005. A tough year to graduate: Iraq, then Afghanistan. The ring is tiny, for a woman, and it has her initials engraved on the inside. Reacher wonders what unlucky circumstance made her give up something she earned over four hard years. He decides to find out. And find the woman. And return her ring. Why not?”

What follows is adventure and mayhem, but in a good way.

I caught up with Lee Child via email and asked a few questions. Visit him at www.leechild.com.

Q: Midnight Line involves the nation’s opioid epidemic, which you treat in a realistic, well-researched way.

A: I’m not really an issues writer, and certainly not a ripped-from-the-headlines guy. I write about what’s on my mind at the time. I guess I was thinking about how to solve problems in general, and how a good place to start would be to face the actual facts, some of which are no doubt inconvenient. For instance, I thought, the opioid epidemic.

Q: In 2012, when Jack Reacher was about to be released, the obsessive issue among your fans was the disparity in physical size between Reacher and Tom Cruise. Reacher is 6 feet 5 inches and 250 pounds, Cruise is 5 feet 9 inches and 150 pounds.

A: Casting Reacher was like a Venn diagram that didn’t meet in the middle. Actors with the talent to put a largely internal character on the screen are a tiny, tiny subset. Actors 6’5” and 250 pounds are a tiny, tiny subset. Actors who can attract big financing are a tiny, tiny subset. There was no overlap. Cruise killed two categories stone dead and failed the third. In the real world, he was the perfect guy. I know he’s happy with the movies, and so am I.

Q: No Middle Name was released last summer, consisting of a new novella and the “complete collected Jack Reacher short stories.” At the same time, Night School, a novel set in Reacher’s past, came out. They formed a foundation for understanding how Reacher’s past informs his present. Are there more short stories on the way, and will you take Reacher back in time again?

A: I like the prequel novels and stories and I’m sure there will be more. I can’t truthfully say I’m planning any, but only because I don’t plan anything. For that reason, I can’t tell you much about the novel for 2018 yet, because I haven’t finished it and I don’t know what is going to happen next.

But this is how it starts: Reacher is passing through New Hampshire and he sees a road sign to a place he recognizes from old family paperwork as his late father’s place of birth. He goes to take a look, but there’s no record of a family named Reacher ever living there.

Q: You’ve been conjoined to Reacher for more than 20 years. What issues do you two have with each other?

A: I think it’s dangerous for a series writer to get too fond of his main character, so I keep him at arm’s length and I do him no favors. I aim to like him a little less than you’re going to like him. That keeps him honest. And humble. Always remember: I’m not afraid of Reacher, he’s afraid of me.

Q: You write a day-to-day blog during book tours, and by now your fans must feel they know everything about you. But what’s one thing they don’t know?

A: There’s nothing surprising about me. I’m a very ordinary guy. Except I really like ironing.

Q: What’s the question you want to answer that I have not asked?

A: I was asked a brand-new question last week: What three criminals would you like to have dinner with? I haven’t decided yet.