This is the latest installment in an occasional First Read series looking at the candidates’ financial disclosures.

For the surging Newt Gingrich, his campaign and business interests are intertwined -- and he keeps it all in the family.

A First Read analysis of his financial disclosure finds Gingrich has made millions from companies that bear his name, which his wife and daughter are integral in running, including one that produces documentaries and books Gingrich promotes on the campaign trail. A second source of income is from a talent agency run by his daughter, who plays a key role in his campaign.

But the way Gingrich lists his income raises questions of transparency. Most of Gingrich’s income -- about $2.5 million -- in the year-and-a-half reporting period is listed as coming from Gingrich Productions, the arm of Newt, Inc., that makes the books and movies and where he was a director until he launched his campaign. His wife Callista is the CEO. (The films are produced in partnership with Citizens United -- the same Citizens United that won the landmark Supreme Court case last year that critics contend has opened the floodgates to unchecked money in politics in the form of Super PACs.)

But Gingrich’s campaign says it’s not accurate to say he got the money from “Gingrich Productions” alone. Before he ran for president, Gingrich spokesman R.C. Hammond said, Gingrich combined “Gingrich Productions” and “Gingrich Communications.” Any speaking fees, Gingrich’s FOX contract, and some advisory boards he served on, for example, were paid to “Gingrich Communications” and not to Gingrich directly, Hammond said.

Gingrich told the AP today that he didn’t need to be a lobbyist, because he made $60,000 a speech. But the speeches, the FOX contract, and the boards are not itemized, so there’s no way to tell from the disclosure how much money he made from each or if he made money from anywhere else.

“Obviously, it’s not transparent,” said Bill Allison, editorial director at the Sunlight Foundation, a transparency watchdog. He added, “It probably doesn’t violate the letter of the law, but it definitely violates the spirit of the law, which is to allow the public to understand who is providing a candidate with income and who he has economic ties to. He should be disclosing what he’s getting from these different companies and these different organizations, and that’s the purpose of this disclosure -- to see if he has a particular conflict of interest.”

Gingrich, who made most of his money after he left Congress, is worth between $7.1 million and $31 million, according to a tally of his assets and liabilities. He made between $2.6 million and $2.8 million in the reporting period (from 2010 through July 2011 when he filed the disclosure).

Gingrich and his wife have held at least nine book signings and screenings this month and at least 19 since July, according to a review of the campaign’s daily schedules. Hammond defended Gingrich’s promotional efforts while he is campaigning.

“What should we do then?” he asked. “Should we remove him from all this stuff? The rules are set up; the rules are being followed. … There are rules on this, it's very clearly outlined, and we follow those rules.”

Hammond also points out, correctly, that rivals Michele Bachmann and Herman Cain also hold book signings on the trail. During Cain’s surge in October, he eschewed the traditional early nominating states and went on a seven-stop book tour that was mixed with campaign events. And since her book was released Nov. 21, Bachmann has held at least a dozen book signings, also mixed in with campaign stops.

“What is the difference then with what Michele Bachmann does and Herman Cain and Hillary Clinton when she was First Lady?” Hammond said. He added that President Obama has made millions in royalties from his memoirs since he became president. And “Newt’s books aren’t all about him,” he said. “They're about the country.”

Obama hasn’t mixed book signings with presidential events, but he, too, mixed politics and book promotion back in 2006, when he was a senator and looked like he might become a presidential candidate. (Examples here and here.)

Obama, however, has also released his tax returns, something Gingrich and the other GOP candidates have, so far, declined to do.

“There’s historically been several candidates who ran more as a matter of self promotion than for a serious candidacy,” said Allison, who is also a former journalist and who helped with a book while at the Center for Public Integrity called, “The Buying of the Congress,” published in 1998 and which included a chapter on Gingrich. “There are people who cash in on the campaigns. The knock on Gingrich was that he would show up in Iowa every four years with a book to promote.”

Allison also notes that Gingrich does something “a little more brazen.” Most candidates say, if you want to know their policy, go to their website. Gingrich, on the other hand, says, “If you want to understand my policy, here’s where you can get it” -- in a book he’s written -- “and you have to pay for it. It’s a very unusual thing for a candidate to do, and there’s a question of some for-profit motive.”

Gingrich’s spokesman, though, says the former House speaker’s run for president isn’t about money.

“Newt is very committed to the race,” Hammond said. “The reason they chose to continue screening documentaries and talking about their books is because they share the values about what Newt and Callista believe. They demonstrate their understanding of our history, of our culture, and our people. This is one way they’re demonstrating to Americans how they understand our world and our country and where we're going in the future.”

Gingrich’s second-largest single listed source of income was about $72,000 -- from The Lubbers Agency. A Lexis-Nexis business records search finds that the CEO of the company is Kathy Lubbers, or Kathy Gingrich Lubbers, Gingrich’s daughter -- who was president of Gingrich Communications and is a senior adviser to his campaign.

Gingrich lists five groups that bear his name on his financial disclosure -- “The Gingrich Group, LLC,” where he was chairman until May; “Gingrich Communications, Inc,” where he was a director until May; “Gingrich Holdings,” where he was a director until May; “Gingrich Productions;” and “The Gingrich Foundation,” a charity foundation, where he is a board member.

He also lists a promissory note from “Gingrich Group, LLC” as being worth between $5 million and $25 million. And his stake in “Gingrich Productions” is listed as being between $500,000 and $1 million.

Most of the rest of Gingrich’s money is tied up in investment funds and bank accounts. But he did make between $5,001 and $15,000 from a rental house in Whitehall, WI; $15,000 from the John Locke Foundation; and $4,000 from the American Family Association; as well as income from dividends and interest.

As far as liabilities go, he lists (of course) that $500,000 to $1 million line of credit at Tiffany (which is marked as closed and paid in full); as well as $50,000 to $100,000 to American Express; and a $15,001 to $50,000 Wells Fargo mortgage for his rental property.

Gingrich lists that he was an advisory board member of Fleishman Hillard, a P.R. firm, for a decade from 2000 to May 2011, but he doesn’t list any salary. His campaign says it was likely included in payments to “Gingrich Communications.” Gingrich also reports no income or salary from -- but lists himself as holding positions with -- Healthtrio Centennial (advisory board, January to present); American Enterprise Institute, the conservative think tank (fellow, 1999 to May 2010); and GE Healthymagination (advisory board, 2009 to May 2011). GE is a minority owner of NBC Universal.

Some other business interests he has some stake in: FLC XXXII 24-Hour Fitness, AT&T, Blackboard, Corning, Discovery Communications, Hewlett-Packard, Quaker Chemical, Raytheon, Walgreen’s, Campbell’s Soup, and Dr. Pepper Snapple Group, among others.

New Hampshire Union Leader publisher Joe McQuaid said Monday on FOX that the paper endorsed Gingrich, in part, because he can appeal to regular voters, more so than Mitt Romney.

“I think it's going to be Obama's 99 percent versus the 1 percent,” McQuaid said, “and Romney sort of represents the 1 percent."

Romney is certainly easy to caricature as the 1 percent -- a scion corporate executive with a net worth estimated to be between $190 million and $250 million. But, according to the IRS, the top 1 percent of income earners in 2010 are those households with an adjusted gross income of $380,354.

By that measure, Gingrich is certainly a member.