This post has been updated.
WASHINGTON -- Newt Gingrich loves selling himself - both as a presidential hopeful and as a for-profit author.
As he seeks the GOP nomination, the former House speaker frequently combines traditional political campaigning with the sales job for his books and films that has earned him millions. As his rivals on Friday scheduled busy days with voters in early nominating states such as Iowa and New Hampshire, Gingrich planned a single public event: a book signing in the nation's capital.
(Update: Gingrich's book signing has been reportedly cancelled due to "public safety concerns.")
Gingrich, enjoying a surge in the polls just a month before the first contests are held, prides himself on his non-traditional campaign style. It isn't clear whether it will pay off politically. But it certainly has not hurt his own income.
Gingrich's personal financial disclosure form shows that he and wife, Callista, reported between $500,000 and $1 million in assets from Gingrich Productions, the couple's media company that produces books and films. The filings also list a promissory note worth between $5 million and $25 million owed to the production company, records show, although details of that asset are unclear.
The July filings list Gingrich's income and assets since early 2010, including rental income, investment dividends and capital gains.
Gingrich has turned over the production company to his wife as he works to build support for his White House bid. Yet he still promotes their films, often hosting screenings on the sidelines during conservative conferences.
Afterward, aides sell DVDs of the programs and their companion books.
It is a routine for Gingrich. He delivers a rousing speech, as he did at the Conservative Political Action Committee conference in Orlando, Fla., this summer; a short time later, he and his wife are at a table signing freshly purchased copies of their books. The same thing happened last week at events in South Carolina.
It is all legal, said former Federal Elections Commission chairman Dave Mason.
"The basic rule is that he can do both things, as long as he doesn't use any revenues from the book tour to subsidize the campaign, and as long as he doesn't use campaign funds in a way that benefits him personally," said Mason.
For Gingrich, a former history professor, the books and films are a point of pride, and he seems programmed to promote them.
When asked last week about Russia during a town hall-style meeting in South Carolina, he noted that he made a film about the Ronald Reagan-Margaret Thatcher-Pope John Paul II nexus that he posits helped bring down the Soviet Union. Any mention of "American exceptionalism" earns a mention of his movie on the subject of America's special role. And his film and book about Reagan seldom go unmentioned as he hails the former president as a role model.
"I've done a movie on Ronald Reagan called `Rendezvous with Destiny,'" Gingrich told CNBC this week. "Callista and I did. We've done a book on Ronald Reagan. You know, I campaigned with Reagan. I first met with Reagan in `74. I'm very happy to talk about Ronald Reagan."
Even when asked about real estate mogul Donald Trump's upcoming debate for GOP hopefuls, Gingrich can't help but plug the connection: Trump appeared in a Gingrich film.
At times, there seems little distinction between his campaigning and bookselling.
For instance, before a one-on-one debate with then-contender Herman Cain outside of Houston, Texas, the Gingriches signed copies of their books for fans who lined up to buy an autographed copy just outside the venue's doors. Nearby, a volunteer donned an elephant costume and stood in for the star of Callista's children's book, "Ellis the Elephant."
For Gingrich, the campaign sometimes takes on the feeling of an extended book tour.
"At 8:30 tomorrow morning, we're going to be at the Westin at the Detroit Metropolitan Airport, and we're going to be talking about jobs and the economy," Gingrich told a radio interviewer last month. "And then after the town hall meeting, Callista is going to be signing her new book, the New York Times bestseller, `Sweet Land Of Liberty.' ... And I'll be signing my new novel, `The Crater,' about the Civil War, and a book on American exceptionalism called `A Nation Like No Other.'"
Gingrich, meanwhile, continues to run a campaign perhaps like no other.
Associated Press writer Jack Gillum contributed to this report.