The novelist Tom Clancy is best known for writing which genre of novels?

Thomas Leo Clancy Jr. (April 12, 1947 – October 1, 2013) was an American insurance agent and novelist. He is best known for his technically detailed espionage and military-science storylines set during and after the Cold War. His literary career began in 1984 when he sold his first military thriller novel "The Hunt for Red October" for $5,000 published by the small academic Naval Institute Press of Annapolis, Maryland.

He is also known for his multiple video games series that include "Tom Clancy’s Rainbow Six" and "Tom Clancy’s Ghost Recon". Seventeen of his novels have been bestsellers and more than 100 million copies of his books have been sold. His name was also used on movie scripts written by ghostwriters, nonfiction books on military subjects occasionally with co-authors, and video games. He was a part-owner of his hometown Major League Baseball team, the Baltimore Orioles of the American League, and vice-chairman of their community activities and public affairs committees.