Once upon a time, there was an advertising man in Salt Lake City who decided to write a story for his two little daughters.

"I write great radio ads," he said. But he had never written a story. He also knew something about marketing.When he finished his story less than a week before Christmas in 1992, he decided he should share it with his mother and other members of his family.

So he had 20 copies printed. His family liked his tale of a father who learns one Christmas about the most precious gift of all: a parent's love for a child. They passed his little book around.

By February 1993, people were coming into bookstores asking for copies of the story, titled "The Christmas Box."

"After one bookstore called up and said they'd received 10 orders that week, they suggested I publish it," said the author, Richard Paul Evans, a partner in Twede Evans Advertising of Salt Lake City. "So I sent it to all the regional publishers. They all rejected it."

It was just a Christmas story from an unknown author, is the way he recalled the general reaction. It had no pretty pictures. And it had an awkward length, "too short to be a novel, too long to be a short story."

Evans, 32, decided he would publish his story himself. He named his publishing company Steinway, after two of his favorite authors, John Steinbeck and Ernest Hemingway.

His little story ran 87 pages in paperback. It tells of a young couple named Richard and Keri (just like Evans and his wife), living in cramped quarters with their daughter, named Jenna (just like one of Evans' daughters), who answer an advertisement to care for an elderly woman named Mary in her elegant old Victorian mansion.

And there, as Christmas approaches, the story unfolds. Richard, who is often too preoccupied with work to go with Keri to Jenna's dance recital or to play with the little girl, encounters an old box and hears music in the night and dreams of an angel, who, with Mary, holds the key to mysteries and wisdom.

"We brought it out around October 1993 in the Salt Lake City market expecting to sell 3,000 copies," Evans said of the book. "We sold out two weeks before Christmas at 20,000 books."

Next Sunday, "The Christmas Box," priced at $4.95, will appear in the No. 2 position on The New York Times paperback best-seller list.

"We received orders all year long," Evans said. "We released it nationally in September of this year, and since that time we are just about up to 400,000 books that have been shipped out. Evans chose 20 markets, concentrating mainly in the West, where he grew up.

"What's amazing about this book is our distribution is still not close to what most books have. I figure we're in about one-fourth of the bookstores in this country."

In Roy, Utah, he said, a bookstore told him of selling 4,000 copies. A woman called from a little store in Montana and said she was selling 300 copies.

"Every bookstore tells me people buy one and come back and buy one for everyone they know. It's an exponential growth."

Evans is no longer an unknown author. "I've been called by just about every major publisher in the world," he said.

Movie companies are interested in him. He optioned the rights to his book six months ago, he said. People want merchandising rights and rights to publish a hard-cover version of "The Christmas Box."

Evans said he was bidding farewell to advertising and was out of the self-publishing business, too.

"I'd rather write than publish," he said. He has started writing the prequel to "The Christmas Box," because people are asking him to tell of the days when Mary was young.

He hopes to finish "Timepiece" by March, perhaps for publication by Mother's Day.

Evans said the success of "The Christmas Box" had been like a dream. Though others have found that the book speaks to them, it remains a message from Evans to his children. "When they are older, they can read it, and they can appreciate the depth of my love," he said.