What do you get when you cross the stoic vigilantism of Dirty Harry with the brutality of an Ultimate Fighting champion and package him in the body of an NFL Linebacker? For more than 50 million readers of action/crime author Lee Child's 16-book series, the answer is obvious -- Jack Reacher.

Reacher is the inscrutable hero of Child's hugely successful novel franchise. A former U.S. Army military policeman, a West Point graduate, and a one-man wolf pack, Reacher travels America by bus, never looking for trouble but always finding it, and dispatches villains with unflinching brutality.

In 1997, Killing Floor, Child's first Jack Reacher book, was optioned by Hollywood for a paltry $100,000.  Producer Mark Johnson, then a recent Oscar-winner for Rain Man and currently the executive producer of AMC's critically-acclaimed Breaking Bad, had the prescience to bank on adapting Child's debut for the screen. As with so many development deals, that deal never developed. But now Jack Reacher's journey from niche pulp-novel protagonist to Big Screen Hero is taking a significant turn.

One Shot, Child's ninth book, is currently finishing production as a big-budget action thriller starring Tom Cruise as Jack Reacher.

The casting decision was not without controversy. In an interview with The Guardian last summer, Lee Child admitted that fans of his books thought Tom Cruise - who at 5'7 stands nearly a foot shy of Reacher - wasn't big enough to play the larger-than-life character. But with production set to wrap this winter, Child has become a believer in Cruise's capacity to live up to the role, and to carry Jack Reacher into what could be a franchise as lucrative and even longer-lasting than Matt Damon's Jason Bourne trilogy. Reacher's size in the books is a metaphor for an unstoppable force, the author told The Guardian, which Cruise portrays in his own way.

Produced jointly by Paramount Pictures and Cruise's production company, along with Skydance (a production company owned by the son of Oracle CEO Larry Ellison), One Shot is directed by Mission: Impossible-Ghost Protocol helmsman Christopher McQuarrie. With an estimated $50 million budget, $1 million of which went to Child for the rights, the film is sure to be marketed as a major blockbuster upon its 2013 release.

Shot on location in and around Pittsburgh, the plot involves Reacher's search for a crazed sniper, reminiscent of the 2002 Beltway sniper attacks in and around Washington DC. In a quirky bit of casting, German Filmmaker Werner Herzog plays the homicidal villain.

For Lee Child, who left a job in TV and began writing the Reacher books 15 years ago, there's vindication in the film's high profile cast and crew. While his first flirt with Hollywood fell flat, this time around the A-list heft, his own best-seller status - and more than a dozen Reacher books to fuel a franchise - has him smiling all the way to the bank.

Still, Child's hardcore fans, known as Reacher Creatures, refuse to be mollified. There's currently a Facebook page called Tom Crusie is not Jack Reacher with 2,300-plus unhappy members. He would of been better cast to play Bilbo Baggins not Jack Reacher, is one comment typical of the lot.

For those Reacher-Creatures grousing about Cruise in their hero's shoes, he has some conciliatory words. In an interview with the Wall Street Journal, Child said, With another actor you might get 100% of the height but only 90% of Reacher. With Tom, you'll get 100% of Reacher with 90% of the height.