“CHAIN SAW CONFIDENTIAL: HOW WE MADE THE WORLD’S MOST NOTORIOUS HORROR MOVIE,” by Gunnar Hansen, October 2013, Chronicle Books, 240 pages, 16-page full-color insert, hardcover, $24.95.

A terrifying tale of murder and insanity, “Texas Chainsaw Massacre” has been revisited, remastered and most recently, filmed in 3D. Yet there’s nothing quite like the first time a story is told. For “Chainsaw,” it was 1974, when the original low-budget horror film hit theaters and rapidly became an international sensation.

Maine has special ties to the legendary movie as the Pine Tree State is the home of Gunnar Hansen, the man cast as Leatherface, the film’s chainsaw-wielding killer.

“I think this was probably the hardest experience I’ve ever had — working on the movie,” Hansen said in a recent interview. He is careful not to reveal exactly where he lives for privacy reasons, but his Maine home is “on the coast” and his fan mail post office box is in Northeast Harbor.

As “Texas Chainsaw Massacre” has grown in popularity, so have the rumors about how the movie was made and where the story came from.

“It’s like the movie has taken on a life of its own, as far as what people think,” Hansen said. “The myths have just gotten bigger and bigger and more entrenched.”

Even today, as the film nears its 40th anniversary, people continue to ask questions: Is the story true? Did people really die during filming?

In Hansen’s recently published book, “Chain Saw Confidential,” he answers these questions by taking readers to the movie set and walking them through the scenes step by step, through the eyeholes of Leatherface’s mask.

“I’ve always had a very good memory,” Hansen said. “I’ve always been very clear in my mind in remembering what went on. That said, I know — as I mention in the beginning of the book — that our memories are a little bit false in that we remember a story as the last time we told it. Stories evolve, so we have to be careful.”

About 20 years ago, Hansen sat down to write all he remembered about his time on the stifling hot “Chainsaw” set. The account, originally intended for personal use, proved useful when he at last decided to write the book.

So what took him so long?

Over the years, Hansen has been approached by several publishers to write a more complete book, but he didn’t see how he could reach a broad audience. When another writer proposed to write it for him, Hansen re-examined the project.

“Originally, I just saw it as a memoir of my experience,” he said. “But what I really needed to do to make it a good book is interview everyone I could find that was involved in the movie.”

In “Chain Saw Confidential,” Hansen quotes the film’s cast and crew to uncover what happened on set when he wasn’t present. He also discusses the film’s impact on the horror genre, its reception by critics and fans, and the elaborate rumors that have flourished since the movie came to theaters.

“I think one of the most common questions I get from fans is, ‘Did I have fun working on the movie?’ And they’re always a little surprised or a little dismayed when I say, ‘No. Fun is never a word that came to mind.’ Making movies is very hard work,” Hansen said. “‘Chainsaw’ is unquestionably the hardest thing I’ve ever done, physically demanding and emotionally demanding and very demanding when it came to acting because I was so limited in what I could use in terms of the character.”

Leatherface never speaks, aside from making odd animal noises. It isn’t within the character’s mental capacity to form words. And since Leatherface is always wearing a mask of human skin, his facial expressions are hidden. Hansen had his work cut out for him.

On top of that, Hansen and the rest of the crew had to work around the limitations of a low budget film — no stunt doubles or special effects. They performed feats that would never be allowed on sets today. For example, Hansen running through the woods in the dark with a real, live chainsaw.

“I was always very aware of how much I suffered and the danger I went through,” he said. “But I didn’t realize how much everybody suffered, particularly Marilyn Burns, who played Sally, the survivor. That was the most revealing interview for me.”

Of course, none of the actors were actually cut to pieces by a chainsaw. While “Chainsaw” has gone down in history as a fantastic splatter film, aside from a little blood here and there, it’s essentially gore-free.

“I think the reason people still talk about ‘Texas Chainsaw Massacre’ 40 years after the fact is you don’t see anything, you imagine it,” Hansen said. “It’s not competing for effects, it’s not trying to outgross you, it’s working on your mind, and I think that’s what reverberates.”

“The horror that stands out is the horror that works on your brain, not just because you imagine what you see, but because you’re confronting something,” he said.

If you’ve never seen the original “Texas Chainsaw Massacre,” now is the time to check it out. With Halloween just around the corner, what better time to dust off some old horror films?

And while you’re at it, you may want to consider some of Hansen’s favorite horror movies, “The Haunting” (1963), “Alien” (1979), “Jacob’s Ladder” (1990), “The Thing” (1982) and “Halloween” (1978).

Hansen tends to be busy around Halloween, attending events such as horror conventions. And for many years, trick-or-treaters avoided his house — and not because of his role as Leatherface.

Children in his neighborhood knew him as the “Wolf Man,” a title he earned after painting himself black and hiding in the bushes one Halloween to scare away trick-or-treaters attempting to throw toilet paper in the trees of the library next door.

“It was a long time before they started coming around the house again,” he said. “Now when I’m home, I always have candy for them.”