Steve Berry, co-president of the International Thriller Writers, delivers his fourth novel to feature ex—Justice Department agent Cotton Malone, The Charlemagne Pursuit.

Where do you get your wildly inventive ideas?

My mailman probably thinks I’m nuts with all the unusual magazines I subscribe to. They come in from all around the world. I also read a lot of nonfiction, and I’m a Discovery Channel addict. Travel is another inspiration. For every book, I’ve visited a location where most of the plot lines for the story were fleshed out and developed. I just returned from France and four days of research. For The Charlemagne Pursuit, I spent several days in the cathedral at Aachen, the last remaining building that Charlemagne himself built.

Templars, Romanovs, Charlemagne—are there still great mysteries to explore?

I hope there are many still out there. I spend an enormous amount of time searching for them. Over the past year I’ve been to Turkey, Ukraine, Greece, Egypt, England, France and Belgium. I found lots of new ideas in all of those places. You don’t necessarily have to visit locations to write about them (that’s why God made National Geographic), but it sure helps.

Is your background in history?

Nope. I’m a lawyer by trade. But I love history. Always have. Especially its mysterious aspects. People are fascinated by things lost—finding them makes for great stories. The kind I love to read.

How do you go about your research?

My book acquisitions are done at a used bookshop in Jacksonville, Fla., that has a wonderful history section. Generally, I use about 200 sources. Certainly, I don’t read all of those, but I do read large chunks, searching for facts that fit my plot.

Who do you read when you’re not reading for research?

Some of my favorites include Clive Cussler, James Rollins, Dan Brown and Eric Van Lustbader. I’m a thriller addict. David Morrell is, to me, the finest thriller writer living today, bar none. I also love historical fiction. Sharon Kaye Penman is a master of that genre.

Will you be doing another in the Cotton Malone series?

There will be at least two more Cotton Malone books. My hope is that he’ll continue on for many years to come.

You’ve said it took seven years and 85 rejections before your first book found a home. What advice do you have to other authors who find themselves in a similar position?

It’s a tired old cliché, but it’s also a solid truth—never, ever give up. Somebody’s name is going to be on the cover of a book—it might as well be yours .