NEW YORK (USA TODAY) - Bill O'Reilly describes himself as a journalistic "watchdog" and a "champion bloviator."
He's not a historian - "not really. That's not my discipline," he says in his corner office at Fox News, home of The O'Reilly Factor, the top-rated show on cable news.
But few history books can approach the popularity of O'Reilly's Killing Lincoln, which has sold more than 2 million copies since it was released a year ago. His new book, Killing Kennedy (Henry Holt), about the 1963 assassination of President John F. Kennedy, could be as popular. It goes on sale Tuesday.
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Both books were co-written by Martin Dugard, who did most of the research, leaving the writing to O'Reilly, whose approach is to write "history that's fun to read" in a "populist way. No pinheaded stuff, just roar it through!"
It's history as fast-paced thriller, with dramatic foreshadowing in a you-are-there present tense. And, O'Reilly says, "it's all true!"
A few historians questioned details and a lack of documentation in Killing Lincoln. O'Reilly, a former high school history teacher, says any errors, corrected in later editions, are "picayune." The criticism, he says, is just jealousy.
"These guys toil in obscurity their whole lives, and a punk like me comes along and sells 2 million copies. They're not happy."
O'Reilly, 63, is to traditional history what best-selling novelist James Patterson is to literature. Neither gets much respect from academic types. Both say they don't care - all the way to bank.
""I know that Oswald killed Kennedy. Now, was he pushed? Encouraged to do it by outsiders? Possibly. Possibly. Was he sitting down with Fidel Castro? No.""
-- Bill O'Reilly
They also share a collaborator. Dugard (whom O'Reilly calls "the best researcher I could find - and I talked to all the top guys") co-wrote Patterson's 2009 non-fiction bestseller, The Murder of King Tut, about a 3,000-year-old mystery.
O'Reilly says he didn't solve all the mysteries of the Kennedy assassination. He found no evidence of a conspiracy but stops short of ruling it out.
"I know that Oswald killed Kennedy. Now, was he pushed? Encouraged to do it by outsiders? Possibly. Possibly. Was he sitting down with Fidel Castro? No."
But he adds, "There were people around Oswald who shouldn't have been there." He cites George de Mohrenschildt, a well-educated Russian immigrant with possible CIA connections, who "had ties to some very, very important people. Why is he hanging with this loser (Oswald)?"
De Mohrenschildt pops up in other books on the assassination. He's even a minor character in Stephen King's best-selling novel 11/22/63. But O'Reilly has a personal connection.
In 1977, as a Dallas TV reporter, O'Reilly tried to interview de Mohrenschildt, who also was a target of congressional investigators re-examining the assassination.
As O'Reilly tells it, as he knocked on the door of de Mohrenschildt's daughter's house in Palm Beach, Fla., he heard a shotgun blast. Police later ruled that de Mohrenschildt committed suicide.
"There were rumors he was murdered," O'Reilly says, "but I found no evidence of that." He adds, "I'm still working the story. There's something there. What it is, I just don't know."
O'Reilly's biggest surprises were "how crazy, and I mean crazy," Oswald was, and "how little the authorities did to protect Kennedy" in Dallas.
Two-thirds of the book deals with Kennedy's presidency and private life, including his extramarital affairs. It portrays Kennedy as a pragmatic and decisive leader who treated sexual risks as "his carpe diem way of living life to the utmost."
"I wanted to show the good and the bad," O'Reilly says.
He says his biggest break was getting FBI agents who flooded Dallas after the assassination to share what they learned about Oswald.
He says that helped him understand the assassin, a former Marine who defected to Russia, then returned to the USA with his Russian-born wife, Marina.
For a taste of O'Reilly's style, consider his description of Oswald on the eve of the assassination as he visits his estranged wife.
As O'Reilly sets the scene, Oswald is undecided about shooting Kennedy as he begs his wife to take him back.
"But if she doesn't, " O'Reilly writes, "Oswald will be left with no choice."
"That's how delusional Lee Harvey Oswald's world has become. He now deals only in absolutes: either live happily ever after - or murder the president."
O'Reilly may not be a historian, but his office walls are filled with historic artifacts, including the last South Vietnamese flag to fly over the U.S. Embassy in Saigon and the errant Chicago Tribune front page proclaiming "Dewey Defeats Truman."
He boasts, "Everything in here is an original," which could be applied to O'Reilly himself.
His love-him-or-hate-him personality is part of his appeal. To viewers who complain that he shouts, he says, "Turn down the volume. I don't really shout that much. I'm just a loud Irish guy."
He says that the liberal media "don't get me" - that he's not a conservative but a "traditionalist." In 2009, he supported President Obama's financial bailouts and economic stimulus, which, he says "led to a big brouhaha with (Rush) Limbaugh." Now, O'Reilly complains, Obama "has lost control of the economy." Mitt Romney, he says, can't connect with "the guy making $40,000 a year."
He writes popular history "to get people engaged with their country." He complains that few history books are fun to read: "Even the really good ones, by Robert Caro and these guys - I mean, they're brilliant guys, but to get through 800 pages, you either have to be retired or on vacation for six weeks."
For those keeping score, Caro's fourth book on Lyndon Johnson, The Passage of Power, is 712 pages, including 79 pages of footnotes and sources. Killing Kennedy is 325 pages, including seven pages about its sources.
The Passage of Power landed on USA TODAY's Best-Selling Books list at No. 15 and spent seven weeks in the top 150. Killing Lincoln landed on the list at No. 3 and has been in top 50 for 42 weeks. It's now No. 38. (A kids' version, Lincoln's Last Days, landed on the list at No. 42 and is now No. 61.)
No history book has sold so well since David McCullough's 2001 biography, John Adams, which was adapted as an HBO miniseries. A two-hour version of Killing Lincoln, narrated by Tom Hanks, will be on National Geographic in February.
But beyond its commercial success, Killing Lincoln got mixed reviews. Its "narrative flair" was praised by University of New Hampshire historian Ellen Fitzpatrick in a Washington Post review, but she said it "offers no direct citations for any of its assertions."
Rae Emerson, deputy superintendent at Ford's Theatre, site of Lincoln's assassination, cited seven errors in the book - such as references to Lincoln in the Oval Office, which wasn't built until 1909.
O'Reilly says he invited anyone who challenged his facts to appear on his TV show, but no one would. Emerson didn't respond to questions from USA TODAY.
As with Killing Lincoln, Killing Kennedy doesn't always name names or cite its sources.
It describes a 1962 party at Bing Crosby's home and a rendezvous between Kennedy and Marilyn Monroe this way: "There is an intimacy in their movements that leaves no doubt they will be sleeping together tonight."
O'Reilly says that's based on an article in the British tabloid Daily Mail, confirmed by a federal agent who was at the party.
"I don't want to sound defensive, but either you believe what we wrote, or you don't," he says. "I'm not writing a Ph.D. dissertation."
Douglas Brinkley, a Rice University historian and prolific author (most recently of the biography Cronkite), says that popular history often omits footnotes and that O'Reilly shouldn't be "held to a double standard because of his politics."
But Brinkley adds that the Kennedy assassination remains a heated issue, and "whatever O'Reilly writes, it will be picked apart. The lack of footnotes and details about its sources make it harder to find the book's frailties. But someone will find them - if they are there."