The Sum of All Fears is a political thriller novel, written by Tom Clancy and released on August 14, 1991, as the sequel to Clear and Present Danger (1989). Main character Jack Ryan, who is now the Deputy Director of Central Intelligence, tries to stop a crisis concerning the Middle East peace process wherein Palestinian and former East German terrorists conspire to bring the United States and Soviet Union into nuclear war. It debuted at number one on the New York Times bestseller list. A film adaptation, which is a reboot of the Jack Ryan film series and starring Ben Affleck as the younger iteration of the CIA analyst, was released on May 31, 2002.

Thomas Leo Clancy Jr. was an American novelist. He is best known for his technically detailed espionage and military-science storylines set during and after the Cold War. 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 screenplays 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, and vice-chairman of their community activities and public affairs committees.