Tom Clancy, the wildly successful military and spy novelist, died Tuesday in a hospital in his hometown of Baltimore, the New York Times reports. He was 66.

The president of G.P. Putnam’s Sons, Clancy’s publisher, did not provide a cause of death, according to the Times.

Clancy’s books, revolving around the Cold War and its aftermath, spawned a many-million dollar industry that crossed over into film and video games. Thrillers like The Hunt for the Red October (1984), his first novel, and the Sum of All Fears (1991) were converted into blockbuster films starring Sean Connery and Ben Affleck, respectively, and also served loosely as plots for video games by the same names.

The former insurance broker became a prolific published writer through three decades, with his next book, “Command Authority,” scheduled for publication on Dec. 3. But in 2002, on release of Red Rabbit, he told TIME that writing remained a chore.

“I don’t recommend writing as a form of employment, because it’s such miserable work,” he said in an interview. “That’s how you tell a rookie: if they actually think the writing’s fun. I guess it is for the first one or two, but after that it just becomes miserable work, like digging in the dirt with a shovel. But it’s something you have to do. You can’t not do it.