Leif Peterson didn’t set out to write a page-turner.

A friend from grad school had given him a writing prompt, just for fun. Peterson’s assignment was to write a 1,000-word story about a man who sees his own face on a missing-person poster.

He wrote about a man who stops at a flower shop to buy his wife a bouquet for their five-year anniversary. While leaving the florist, the man sees his face on the poster, hurtling him into terrifying uncertainty.

When he reflects on the last five years — no easy task, considering certain mysterious gaps in his memory — he begins to wonder whether the life he thinks he remembers is a lie.

The story ended on a cliffhanger and Peterson posted it on his Facebook page. Friends who read it demanded more — he couldn’t leave them hanging like that. So Peterson posted another installment of the story, and then another.

Four months later, he had an entire novel on the social networking website.

Peterson, 45, has been writing since graduate school.

He grew up in Baltimore but has a long connection to the valley; his father grew up in Kalispell, and Peterson spent his summer vacations at Flathead Lake.

He now lives in Whitefish and has been a Flathead resident for the last 16 years.

“When we moved here, it was like coming to a second home,” he said.

Peterson earned a bachelor’s degree in English at Whitworth University in Spokane and went on to pursue a master’s degree in English literature at the University of Colorado in Boulder.

“I went to grad school because I wasn’t ready to be done with school,” he said.

It was in Boulder that Peterson started writing his first novel, which ended up becoming his graduate thesis. But Peterson kept writing, and his first book, “Catherine Wheels,” was picked up by Random House and published in 2005.

He since has written “Normal Like Us,” a book of short stories, and a young adult novel, “Silo.” Technical writing gigs help pay the bills, he said.

While Peterson never has restricted himself to a specific genre, “Missing: The Facebook Novel” was an even further departure from his usual writing style, thanks in large part to his publishing medium.

“I don’t normally write page-turners,” he said.

But when he started posting sections on Facebook, the page-turner happened naturally.

“I was trying to write cliffhangers so people would want to come back,” he said.

And they did come back. Peterson’s faithful readers pounced on each new post. Peterson worked Monday through Friday, usually taking weekends off. He would wrap up his daily writing session by noon and post the latest installment online.

It was a unique experience for Peterson, who is used to editing stories as he writes. Computers allow him to go back and revise earlier-written sections or make plot adjustments.

Posting “Missing” on Facebook took away that power.

“It was basically like Charles Dickens. I couldn’t go back and change things,” he said.

But somehow, the story worked. And when, after 84 installments, Peterson wrapped up the book, he knew he had something special on his hands.

He made a few minor, primarily grammar-related edits to the story and then self-published the book. He’s hopeful a publisher will pick it up.

Those who buy the book have the option of experiencing the story as it was first written. Peterson included asterisks to mark the end of the original installments; readers are free to read it in sections.

But in doing so, they may feel the same way Peterson’s Facebook readers felt when the story wrapped up.

“It was a bittersweet ending because it was over,” he said.

As far as Peterson knows, his is the only book to be written specifically for serial publication on Facebook. He enjoyed the experience and, while he has no plans to write another book online, he would not rule out the idea of doing it again.

“It was interesting. I might do it again if I had a concept,” he said.

“Missing” and “Silo” are available at www.leifpeterson.com. Peterson’s other books are available on Amazon.com in print and Kindle formats.

Reporter Kristi Albertson may be reached at 758-4438 or at kalbertson@dailyinterlake.com.