When Scott Eyman set out on the trail to do his all-encompassing biography on John Wayne, the material he was about to cull on the late film icon was immense, but the idea was simple: get the Duke's story right.

Eyman knew to tell that story, it was going to take him as long as four to five years -- but the investment in his new 657-page tome, "John Wayne: The Life and the Legend" (Simon & Schuster), as he discovered, was more than worth it.

"Writing a biography is just a huge, huge investment of time, and it's got to be something I'm really interested in -- a question I want answers to and a riddle I want to solve. So, in a sense, I'm getting paid to learn about someone who fascinates me, and who was ill-served, previously by other biographers," Eyman told me in a recent interview. "Some people have good books written about them and others don't. I thought there were a couple of good books about John Wayne -- his daughter Aissa's was good, and the Randy Roberts book was OK, but that was about it."

Eyman said his real concern about the previous biographies written about Wayne since he died in 1979 at age 72 was that he was "viewed through one prism -- and that was politics" (Never mind, of course, that the actor had starred in such classics as "Sands of Iwo Jima," "True Grit," "The Alamo" and "Rooster Cogburn," among several others).

"If a conservative had written about him, then John Wayne was the risen Christ, but if a liberal wrote about him, he was a draft-dodging, war-mongering hypocrite, and that was pretty much it," Eyman said. "I thought, 'Well, since this is 2010, let's just take that single lens of politics away. We all knew he was conservative, let's see who he was as a husband, as a father, a producer a co-worker and an actor."

That's not to say Eyman ignored Wayne's political life entirely. It just came down to taking a different approach to writing about the life of the man born Marion Morrison -- a man who kept his true identity and never legally changed his name.

"I thought to myself, 'What a concept? Writing about John Wayne, the man,'" Eyman said with a laugh. "I just wanted to investigate all of the other facets of his life before the stuff that's already been written about. I wrote most of the book first, and then I went back and did the political thread, because I had some new stuff. But I wanted to first investigate the other aspects of his life and times."

Eyman said his approach to writing about the political aspects of Wayne's life was simple: don't be judgmental, no matter what his own political affiliations were. He was doing something that every journalist, whether they are writing a book, article or newscast should be doing -- he was being objective.

"It didn't matter what I was writing about, whether it was an extramarital affair that he had or his politics, I don't automatically vault for the moral high ground," said Eyman, who interviewed more than 100 of the actor's family members, co-stars and associates for the book. "I don't adapt an attitude of moral superiority to my subject about anything they do unless it's some extreme thing. There are some people that people who do that and are constantly wagging their finger, but I don't get the point of doing that. I think people who like that are sucking up to their readers or sucking up to their audience.

"I try to write effectively, and lay out why he or she did what they did at any given point, according to the evidence, to the letters and the interviews. If I can't ascertain what the motivations were according to those letters, interviews or anything, I just lay out a couple possibilities and let the reader make up their mind."

Fortunately for Eyman, there was no speculation about Wayne's personality, because he had the unique advantage of interviewing him as a 21-year-old journalist. The conversations they had turned out to be invaluable, because instead of asking Wayne the obvious questions, like about the actors he worked with and so on, Eyman instead queried the Duke about the filmmaking process -- a process few actors truly love.

"Because I asked him -- and I didn't know this at the time -- but because I asked him process-oriented questions, and about directors and locations, he opened up to me. I happened to hit a nerve because he passionate about the process of making movies," Eyman recalled. "He was a journeyman film man. Everybody likes the money and the movies, and everybody likes the power movies give you in terms of publicity and getting good tables at restaurants, but very few people actually like making the movies because it's a pain in the a-- and not a lot of fun. You act for 30 seconds, and you wait for an hour and a-half while the re-set the lights. It's boring and hard to maintain a lot of psychological edge over the time you're on the set, which is why they pay actors so much money."

But to Wayne, an Iowa native, the set and everybody that had to do with it was his favorite place to be, Eyman said.

"He was a blue-collar guy, basically, who did all these different kinds of crafts in movies. He made props, he'd done costumes and he'd done stunts. He'd done all different kinds of things that went into making movies," Eyman said. "He really liked the process of making movies, and that's why he was a workaholic. He wasn't doing it because of the money. It wasn't his job. It was his hobby. He liked getting to the set at 7 o'clock in the morning and leaving at 6:30 in the evening. He liked joshing with the stunt men, working with young actors and playing chess between shots. He liked the whole thing."

Tim Lammers is a nationally syndicated movie journalist and the author of the new ebook Direct Conversations: The Animated Films of Tim Burton (Foreword by Tim Burton).