It’s not easy to create an iconic character, but that’s what Lee Child, 63, has done with Jack Reacher. A former major in the Army’s Military Police, Reacher is a supersize human fighting machine who roams the United States with no particular purpose, carrying only a wad of cash and a toothbrush. Thanks to his skills in sharpshooting and hand-to-hand combat, he also effortlessly vanquishes the many nefarious types who invariably cross his path.

In his 23rd outing, “Past Tense” (Delacorte Press, 382 pp., $28.99), Reacher finds himself in bucolic New Hampshire, digging for his family roots. What he finds is a big surprise — and, of course, more brawling.

Child spoke about the book with Newsday by telephone; the conversation has been edited for length and clarity.

Q: Did you think of this book as an origin story for Reacher when you started it?

A: I don’t make a plan, I don’t make an outline — I don’t want to know what’s going to happen. But I wrote that first paragraph and realized that I used birdwatching-type imagery about the migration of birds. And about the only thing we know about father from previous books is that he was a bird-watcher. So I thought, “Why have I done it that way? Well, this is obviously going to be the book about his father.”

Q: At the beginning, Reacher comes to literal a fork in the road and, as usual, he picks the option that leads him into trouble. How does this always happen to him, no matter where he is?

A: It’s only once a year. The other 364 days, Reacher shows up somewhere and nothing happens. I say to people that I write those books as well, but my publisher won’t publish them because they’re too boring.

Seriously, there’s definitely a convention in fiction that the reader is going to give you one free pass and then the rest of the book better be absolutely logical and correct. The one free pass that they give me is that Reacher takes a fork in the road and it leads to trouble. I guess that’s the nature of series: Something always happens. It’s harder with Reacher, of course, because he does not have a job. If you were writing a police series, then it’s automatic: Every day you’d have five problems.

Q: He never shies from a fight, but why does he seem to especially relish beating up bullies?

A: Partly this is because bullying is obviously a very unpleasant thing, but also he thinks that they’re phonies. Being a bully is basically about threatening and Reacher is contemptuous of that: “What has this guy got? What is he going to threaten me with?” So it becomes a contest of arrogance, which is not particularly attractive, but it’s a big part of Reacher’s character. He fundamentally dislikes the fact that the bully is unrealistic.

Q: There’s a scene in the new book where Reacher almost goes down. Almost. Would he ever lose a fight?

A: It’s part of the mystique of the books: He will always win. I wanted to do that as an antidote to all the books I was reading where the hero is incapable or worried or something like that. We all get that in our regular lives, we’re always worried or scared of something. So I thought, “Let’s make this guy completely invulnerable.”

Q: What do you think of the fact that Reacher’s life, which is free of responsibilities, has become a dream for an increasing number of people?

A: The series started in 1997 and the first big emotional boost was 9/11, when people were saying, “We need a real Reacher, we need people like this.” The second big boost came in 2008, 2009, with the financial crash, when people realized that owning stuff, chasing stuff is a liability more than a pleasure. And that turned people on to the idea of, “Wouldn’t it be great to have nothing, to live with nothing?” In a way the times caught up with Reacher’s lifestyle.

Q: Can you tell us a bit about the TV adaptation you’re working on?

A: The idea would be to do a long series on something like Netflix, with 12 to 13 episodes per season. A book probably would not sustain an entire season, so what they would probably do is pick about eight of the books for eight seasons, then cannibalize the other 16 or so books for the best bits — so you get one book plus extra good bits per season. But the deal isn’t done yet, we’re still negotiating.