In the early 2000s Dan Brown, a schoolteacher in Exeter, New Hampshire, had written three novels, each of which had sold at best a few thousand copies. Writing was bringing him neither fame nor fortune.

After finishing his fourth novel, Brown tried something new. “When you’re done with a book, you know every word,” he says, and there’s rarely a need to go through it again. But with that novel, he got an advance reader’s copy before publication, sat down and read it from start to finish. “And I thought, if this doesn’t work, I don’t understand the publishing business. And if people don’t like it, then clearly I need to do something else.”

That book was “The Da Vinci Code.” It has sold more than eighty million copies around the world, and that, dear reader, is a staggering number. If there’s anything that will turn a writer’s head upside down and inside out, it’s going in one leap from selling three thousand books to eighty million. So did Brown buy a chateau in the south of France and spend his days lying in a hammock and gazing out on the beckoning waters of the Mediterranean? No, he went back to his desk in New Hampshire and started working on another novel.

“The thing I learned very, very quickly,” he says of his mindboggling success, “is that it doesn’t change the process. You still, when you go to write your next book, are sitting at your computer, staring at a blank screen. Your characters don’t care how many books you’ve sold. They still require your attention.”

He is now promoting his new novel, “Origin,” the latest in the series featuring the adventures of Robert Langdon, a professor of religious iconology and symbology. When writing, Brown, fueled by a concoction called “bulletproof coffee,” gets up at four in the morning and goes to work in a room with no phone or internet to distract him. The coffee may not be the key to his success, but it clearly doesn’t hurt. The secret ingredients? Butter and coconut oil. “Put it in the blender,” Brown says, laughing, “and I promise you will have the best day you’ve had ever.”