Bill O'Reilly appears on the Fox News show, "The O'Reilly Factor,"Jeff Christensen/ AP

Bill O’Reilly has become the most popular historian in America with his two books on Lincoln and Kennedy atop The New York Times best-seller list.

He has also revealed to The New York Times how he writes his books at breakneck speed, composing well over 1,000 words a day.

He told The Times about his workaholic habits, which includes the best sellers and personally writing his own show which goes out to three million viewers nightly on Fox.

“I work harder now than I have ever worked in my life, which is kind of insane,” O’Reilly said.

He works with co-author Martin Dugard, also co-author of several best sellers before he linked up with O’Reilly, but O’Reilly does all the interviews.

“He basically does the research, and I write it, and we go over every line together. I supply the-you-are-there narrative. It works great.”

O’Reilly does the interviews by phone and tapes them. For the Kennedy book, he said, “I did all the interviews with the F.B.I. guys, and they never talk to anyone but they  “trust me.”

“I can write 1,000 words in my sleep,” he said. “I write for the ear, not for the eye."

He works on his books on weekends, especially after mass on Sundays at his home in Manhasset.

He says Lincoln would have loved his book on him “because it is simple and he was a really simple guy, straightforward guy. He didn’t like a lot of subterfuge or a lot of nonsense.”

O'Reilly is not so sure about the Kennedy book and whether JFK would have enjoyed it, “I don’t know if Kennedy would have liked the book “because it really lays him out as far as what he did, and some of it wasn’t very nice. But in the end he comes off as fairly heroic.”

He says he likes the Obamas and features a photo of him with the first family on his desk. “Michelle was very nice to my daughter,” he said

O’Reilly had to struggle to redefine himself as an historian. His publishers wanted more of the autobiographical books he had written that had been successful.

Instead O’Reilly, who studied history at Marist College in Poughkeepsie, N.Y, and is a history buff, wanted to change course.

He hired Martin Dugard, who had co-written “The Murder of King Tut: The Plot to Kill the Child King” (2009) and “The Last Voyage of Columbus” (2005).

He starts his new book, subject still a secret, right after Christmas and says it “will be a blockbuster of epic proportions.”

Given his record so far, who would disagree?