Wearing a short-sleeved Hawaiian shirt tucked into crisp jeans that end in sensible shoes, the 50-year-old Andrew Peterson could be a genial math teacher. Or a store manager on his day off.

But Peterson is– quite purposefully– an expert rifleman, accomplished diver, neophyte helicopter pilot and volunteer firefighter, and an action thriller author learning choice lessons about writing along the way.

At age 6, Peterson learned something at a summer camp that would ultimately make its way into the book: how to shoot with a bolt-action rifle. He continued to develop the “hobby,” winning state championships in Arizona and Nevada, beating Marine Corps shooting teams in each.

“Guns have a negative connotation in our society,” he says, visiting Salinas from his obscure in-county outpost between King City and Paso Robles. “If you can get past that, it’s a lot of fun. I’m not a hunter. I’m a target shooter.”

He’s also a volunteer firefighter in the unincorporated South County community of Lockwood. He wanted to give back to the community, he says, which brought him in proximity to some risky business.

“There was a fire about a mile from my house, before the Big Sur fires. Five acres. I was on the front lines– close enough to get sprayed by retardant from the firefighting bomber plane.”

He’s also gone to great depths in his chase for the new thrills.

“I’ve always enjoyed being in the water, so I thought, ‘Why not go [deeper] underwater?’”

He went beyond recreational diving and received technical training in scuba diving off Mexico’s Yucatan Peninsula, exploring uncharted underwater caves and diving 200 feet into shipwrecks off the Bikini Atoll where the government exploded nuclear weapons in the 1940s and ’50s. Called “penetrative diving,” it’s among the most dicey styles of scuba.

He almost admits that the danger is part of the lure, he just has a different name for it: “challenge.”

A self-storage real estate developer for 23 years, Peterson seems equally content with the quiet life afforded him by his remote home, where he lives with his wife of 19 years. But his thirst for challenge has motivated and moved him, and at least once nearly killed him.

“I like challenging things in my life,” he says, “like scuba diving. And helicopters.

“I was training with my [helicopter] instructor, coming in for a Pinnacles landing when we got caught in a downdraft. We were going down into the bank. The instructor and I did the same maneuver in tandem: We applied left cyclic [control stick], turned the helicopter to the left, and followed the contour of the slope, sideways, down to safety.”

Another recent challenge threw up a patch of turbulence: He began writing. A “big Star Trek fan,” Peterson started– but didn’t finish– a script for an episode of Star Trek: Next Generation. He did finish an action thriller manuscript, which he sent to freelance editor Ed Stackler, who’s worked with thriller authors Greg Iles and Ridley Pearson.

“He told me to abandon that book and work on another one,” says Peterson, looking as deflated as if that rejection had just happened.

Maybe because Peterson couldn’t resist the challenge, he did just that: nine months of writing followed by three months of editing until he was “sick of [the manuscript].” He sent it in. And in November 2007, Andrew Peterson became a published author.

“The warm glow from the cabin’s window told a lie. The scream from within told the truth.”

That’s how Peterson’s adrenalized thriller First to Kill begins. The protagonist is Nathan Daniel McBride, a former Marine sniper, CIA operative and assassin (“He’s the only man with the skill necessary to get the job done,” reads the book’s back-jacket blurb). The U.S. government recruits him to defeat a band of rogue would-be terrorists.

The story tackles topical moral questions, like the use of deadly force and torture against terrorism. In a scene in which McBride is coercing information from two “miscreants,” he tells them: “This is an anti-Miranda situation. You do not have the right to remain silent.”

It’s a precisely written story, if unsubtle, with political overtones and a vigorous paramilitary streak– fetish, even.

“Nathan McBride is an anti-hero,” says Peterson. “He’s not a Boy Scout. But he still retains his humanity.”

A sequel is planned as Peterson promotes First to Kill on a book tour of 97 West Coast Costco stores.

“I’m not saying I’ve extinguished all my thrill seeking, but I’m not a kid anymore,” he says. “I don’t know what’s next. I just hope something exciting happens.”

First to Kill is available at Costco, Borders, Amazon and other major online retailers. For more information, go to www.AndrewPeterson.com.