Lexington, KY ? Kim Edwards is sitting on her porch swing when the flower delivery man arrives with two bouquets and a copy of Edwards’ debut novel, “The Memory Keeper’s Daughter.”

The flowers are from her publisher to commemorate the book’s recent ascension to No. 1 on The New York Times list of best sellers for paperback fiction. The book belongs to a florist worker who didn’t want to pass up an opportunity for an autograph.

“It’s been like this,” Edwards says, “one surprise after another, all summer long.”

The 48-year-old author may be a newcomer to writing novels, but not to storytelling. She is an assistant English professor at the University of Kentucky, a graduate of the esteemed Iowa Writers’ Workshop and her collection of short stories, “The Secrets of a Fire King,” fetched numerous awards when published in 1997.

“The Memory Keeper’s Daughter,” the story of a child born with Down syndrome and the web of family secrets and lies that follow, has become a literary phenomenon and the surprise summer reading hit.

At a bookstore in Memphis, one customer approached Edwards to offer an unsolicited but glowing recommendation of the novel. She didn’t realize Edwards was the author.

“Writing is kind of an anonymous thing to do,” says Edwards, who wears thin oval glasses, her brown hair cut above the shoulders. “It’s wonderful for me to see the book out in the world, having its own life, even if not attached to me directly.”

Never once, she says, has a stranger stopped her on the street and recognized her as a best-selling author.

Her brick house blends in with the others in this tree-covered Lexington neighborhood. Less than a mile away is the bustle of downtown in Kentucky’s second-largest city and the university where Edwards works.

Although “The Memory Keeper’s Daughter” was relatively successful in hardcover, with 32,700 copies printed, it really took off as a paperback. There have already been 12 printings and 1.3 million copies produced.

Edwards, who grew up in Skaneateles, N.Y., and graduated from Colgate University and the University of Iowa, read several books about Down syndrome and spent hours visiting families with Down children to help shape the central character of Phoebe. But it’s the other characters and their well-intended yet often flawed choices that advance the plot and keep the pages turning.

Phoebe’s mother, who is under anesthesia when she gives birth to twins, believes her son has arrived healthy while her daughter has died in labor. Unknown to the mother, her husband has told an attending nurse to take Phoebe to a clinic, but the nurse defies his wishes and chooses instead to raise the girl on her own.

Edwards says she has always been fascinated by the concept of secrets, so central to the plots of many literary classics. In preparing her novel, she reread two: “Crime and Punishment” and “The Scarlet Letter.”

“It creates this wonderful tension,” Edwards says. “It can be a very powerful way to pull the narrative forward, to draw the interest even while the complexities of those characters’ lives are unraveling.”

The novel begins during a Lexington snowstorm in 1964 and concludes in 1989, with parallel plot lines revealing the separate adventures of both Phoebe and the rest of her family, who live elsewhere. Edwards says she picked the period to chronicle how attitudes about Down syndrome have changed.

“It was a very pleasurable story to write, even though the characters went through a lot of difficult times,” she says. “All the characters went through some kind of struggle, some kind of growth. They were moving, they were in motion. They were discovering things they might not have known about themselves in different circumstances.”

Although the last few months have been hectic, Edwards has found time to work on her second novel.

What’s it about?

It’s a secret.