Tom Cruise as Lee Childs Fictional Hero in Jack Reacher

Karen Ballard/Paramount Pictures

Tom Cruise (standing) in the title role of Jack Reacher, based on the hero in Lee Childs thrillers.

JACK REACHER, the itinerant head-butting hero of Lee Childs best-selling series of crime thrillers, has finally made it to the big screen. An adaptation of Mr. Childs 2005 novel One Shot, retitled Jack Reacher, written and directed by Christopher McQuarrie and starring Tom Cruise, opens on Dec. 21.

What took them so long? The R! eacher books have been appearing yearly since 1997, and if ever a literary property seemed a no-brainer for the movies, its this one. The books have a strong, original central character and taut, linear narratives, full of action and incident; they often feature strong female characters and are surprisingly popular among women; and there are lots of them 17 titles so far, outnumbering even the original James Bond novels.

They are a franchise built around a former military policeman roaming the United States utterly without baggage, personal or otherwise, righting wrongs according to his own no-nonsense code of justice. Writing in The New York Times, Janet Maslin called Reacher one of the most enduring action heroes on the American landscape.

Mr. McQuarrie, who has worked on several Cruise-related projects (including Valkyrie, which he wrote with Nathan Alexander and produced, and Mission: Impossible Ghost Protocol, for which he did some revisions), knows his way around Hollywood and has a very simple explanation for why it took so long to get a Reacher film made. There are no transforming robots, he said in a telephone interview. There is no paranormal activity.

He added: The problem is that Jack Reacher is not 22, and he doesnt have superpowers. He appears in novels that are detective thrillers, and thats a sort of movie they dont make anymore. How do you market it?

Mr. Child, who worked as a television director and producer in England before becoming a novelist, also knows his way around show business. Not long ago, stretching out his longs ! legs on a! coffee table in the East Side apartment he uses as a writing studio, he leaned back in a chair, and, as if giving a PowerPoint presentation, suggested three reasons the Reacher books might be an awkward fit for the movies.

The first reason is never mind, well come back to the first reason. The second reason is that the books are less eventful or less cinematically eventful than they seem, because a lot of the action takes place inside Reachers head. His thought processes, his quirks, his intuitions are what make him interesting, Mr. Child said. How do you get that out of his head and onto the screen?

The third reason has to do with the stubborn nature of the character. In Hollywood they have these unshakable conclusions, he said. And one of them is that a character must have an arc, must go for a journey and learn something, must be different at the end. But Reacher does none of that. He never changes. He doesnt learn anything, because he knows it all from the beginning.

Even so, there was no lack of Hollywood interest. The books have been under option to one studio or another since the first one was published 15 years ago. But nothing happened until Mr. Cruise and Paramount came along in 2005, after One Shot came out. Mr. Child said he was impressed by everyone involved, especially Mr. McQuarrie, whose screenplay he called outstanding. I bet its the least altered first draft ever, he said. This is not starry eyes. I made my living amongst these wolves for years, and I can tell the good from the bad.

Mr. McQuarrie pointed out that while he has had some success as a screenwriter (his script for The Usual Suspects won an Oscar in 1996), he was far from a sure bet as a director, and his budget was far from large. Until! now he h! ad made only one other film, The Way of the Gun, which came out in 2000 and, despite some good reviews, fizzled at the box office.

He began working on Jack Reacher without a lot of confidence that the movie would ever be made. I didnt think they were thinking, Yes! he said. I think they were thinking, Good luck with that one.

He didnt necessarily write the script with Mr. Cruise in mind, he added, but once Mr. Cruise decided to play Reacher, the project suddenly became something they didnt have a reason to say no to.

This brings us back to Mr. Childs Reason No. 1, which is the problem of casting a Reacher movie. As fictional characters go, Reacher is a little underspecified, which makes readers feel so proprietary about him: in our own heads, we help create the character. But the one thing everyone knows about Reacher is that he is big 6 foot 5 and 250 pounds or so and not bad looking, exactly, but a little intimidating. One of his many female friends in the books describes him as a condom stuffed with walnuts. When word got out that Mr. Cruise, who is neither tall nor walnutlike, had agreed to star in the movie, many of Mr. Childs fans became apoplectic. I know Jack Reacher, and Tom Cruise is no Jack Reacher, one of them commented online.