President Obama stocked up on more than 20 books Saturday in a rare stop at a Washington, D.C., bookstore as part of an effort to support small businesses -- and one of the books he chose is by a Duluth author.

Among the president's purchases at Politics & Prose was "Heart of a Samurai," a 2010 young adult novel by Margi Preus that was named a Newbery Honor Book. It's the story of a Japanese teenager who has a series of adventures that lead him to play an important political role -- and realize his lifelong dream.

Preus spent the weekend at a friend's cabin up the Gunflint Trail, where she had no Internet or cellphone coverage. She learned of the president's purchase only late Sunday when she returned to her home in Duluth.

"My son in Colombia left me a message, saying: 'Obama bought your book.' " I didn't know what he was talking about," she said.

But as she pored through a host of emails and Facebook messages, Preus quickly came to understand.

"I was surprised, but I think it's great," she said.

"Heart of a Samurai" is based on the adventures of teenager Manjiro Nakahama, who is rescued by an American whaler after a shipwreck in the mid-19th century. A folk hero in Japan, Nakahama is not as well-known in the U.S., where he went on to become an ambassador between the two countries.

"I think it's Manjiro's amazing story of courage, endurance and friendship that makes the book," Preus said. "A huge part of what interested me was the bond of friendship and how that can change people's attitudes."

The book has been translated into Japanese, where it has enjoyed popularity as well. Preus said her novel was Amazon's top-selling book in Japan when she visited the country in May.

The president's shopping trip the day after Black Friday was timed to Small Business Saturday, but will likely pique more interest for sparking a regular political ritual -- picking apart the president's book choices.

As a window into what the leader of the free world is thinking, the chief executive's reading list has long been the subject of armchair analysis. President George W. Bush made headlines and sparked speculation, for example, when he told reporters he was reading Albert Camus' existentialist novel "The Stranger" in 2006, a low point in his second term.

No reader aside from Oprah Winfrey can create more buzz for a new book. When the White House announced several years ago that Obama was reading Jonathan Franzen's "Freedom" on his vacation, even before its release, booksellers faced angry customers demanding the much-anticipated novel. (Obama had been given an early copy.)

On Saturday the president bought 21 books in about 30 minutes, most of which was dedicated to chatting with other customers.

His long and eclectic list makes it difficult to find a common theme, much less offer some insight into his state of mind at a particularly troubled moment in his second term.

Nearly half the books are written for children or young adults, and are presumably for his daughters Malia, 15, and Sasha, 12. Or maybe not.

Preus said the core market for "Heart of a Samurai" seems to be primarily readers in grades 4 through 8.

Among the notable reads is "Red Sparrow," a spy novel by Jason Matthews that has been praised for its realism. Russian President Vladimir Putin, Obama's occasional real-life rival, makes a cameo in the book.

But most of Obama's choices lean more toward pure escapism.

"The Sports Gene: Inside the Science of Extraordinary Athletic Performance," by Sports illustrated writer David Epstein, tries to dispel common myths about what makes athletes great. "Collision Low Crossers: A Year Inside the Turbulent World of NFL Football" is an unvarnished look at the National Football League from Nicholas Dawidoff.

Obama's list included little new, literary fiction. James Salter's "All That Is," Anthony Marra's "A Constellation of Vital Phenomena," and Jhumpa Lahiri's "The Lowland" made the list.

He's following Winfrey to Cheryl Strayed's "Wild: From Lost to Found on the Pacific Crest Trail." The memoir of a woman's emotional trek, which includes time spent in northern Minnesota, was Winfrey's first selection when she rebooted her book club.

Others, such as "Heart of a Samurai," are aimed at younger readers. Kenneth Oppel's "Half Brother" chronicles how a teen adjusts to a new family dynamic when his parents take in a chimpanzee. Willa Cather's "My Antonia" is a high school English staple.

The bookstore visit was timed to a campaign to support mom-and-pop businesses. Earlier, Obama tweeted: "When our small businesses do well, our communities do well. Join me and visit a small business near you today to celebrate."

At the store Obama didn't say which of the books he intended to read and which were gifts. He noted only that he has something for every age, "from 5 to 52," he said, referring to himself.

That said, Obama is known to be a devotee of his iPad.

News Tribune staff writer Peter Passi and the Tribune Washington Bureau contributed to this report.