Nelson DeMille's book signing on LI

The new book from bestselling Garden City author Nelson DeMille isn't entirely new: "The Quest" (Center Street, $26), the story of four compatriots chasing a rumor of the Holy Grail through war-torn Ethiopia, was first published almost 40 years ago. Now DeMille has expanded and updated it, almost doubling its length, and returned it to the market. He'll be making Long Island appearances this month; he spoke with us by telephone while on the road promoting the novel.

So what's the backstory of this book?

"The Quest" was originally written and published in 1975 as a paperback original. I think the cover price was about $1.25. It probably sold, if I had to guess, about 2 or 3 thousand copies, so it didn't exactly make an impact on the world of literature. When I wrote it, I was not a best-selling author. When it came out, it didn't really get a lot of attention, but people read it, and they loved it, and I always wanted to bring it back to a larger audience.

In what ways was it updated?

Well, for one thing, it's longer. Another thing, the original had a little bit of a love story, a little bit of a sexual triangle, but I really expanded that part of it. When I was originally writing paperbacks, probably 99 percent of my audience was male. Now, we just did a market survey for the first time and found out that 52 percent of my readers are female. So I said, let's make the love story and the romance bigger.

The other thing was, when I wrote the book originally, I was about Frank Purcell's age, and I could relate to him. Mercado, being an older, crustier, veteran reporter in his mid- to late-60s, was a little harder for me to figure out. Now, 40 years later, I get Mercado. I can get into his head better. It enriched both characters, having seen both sides of the gap.

What was it like revisiting your own work 40 years later?

There were a lot of passages and sentences that made me wince, and I realized that I've probably gotten much better as writer. My dialogue, which is now my hallmark, was kind of clumsy. But some of the descriptive passages were good, and the story line was good. For a young writer who hadn't done much, the plot, the story line and the way it was laid out was good. It was like correcting your term paper after you got a C and now the professor has given you a chance to get an A.

How does religion figure into this book for you?

As I say in the book, even the Catholic Church neither confirms nor denies the existence of the Holy Grail. Does the Holy Grail exist? Sure, it exists, at least as tableware. It was the cup used at the Last Supper. Could you ever find it and prove what it is? Not in a million years, unless it said something on the bottom of it, you know,

"Property of Jesus Christ."

Should your fans be worried that reviving this book has distracted you from writing new material?

Well, I did put the next book on hold because I am on tour now, but the next one will be another John Corey book, which is what everybody seems to want. The break for John Corey was a good break; it was certainly a good break for the author. I think John Corey is ready to come back: fit, tan and rested.

WHAT Nelson DeMille Book Signing

WHEN | WHERE Oct. 6 at 3 p.m. Westhampton Free Library, 7 Library Ave., Westhampton Beach

INFO Free, registration required; 631-288-3335, booksandbookswhb.com

WHEN | WHERE Oct. 10, at 6 p.m., Forest Books, 182 Birch Hill Rd., Locust Valley

INFO Free, 516-759-1489