Palm Beach, Florida

“Let’s shoot the breeze for a bit,” says James Patterson, exuding a relaxed attitude on a recent morning at his Palm Beach home despite the fact that he has 13 books coming out this year. He had 11 last year. To date, the 65-year-old author has published 95 books—his most recent, “Guilty Wives,” hit shelves this week—and according to Nielsen ranks as the country’s top-selling author.

Those numbers have added up to big business: Mr. Patterson earns more than $80 million a year, according to people familiar with his publishing empire.