Thomas Leo "Tom" Clancy Jr. was an American author, best known for his technically detailed espionage and military science storylines set during and in the aftermath of the Cold War. Seventeen of his novels have been bestsellers, and more than 100 million copies of his books have been sold. His name is also a brand for similar movie scripts written by ghostwriters and many series of non-fiction books on military subjects and merged biographies of key leaders.

Originally an insurance agent, Clancy launched his literary career 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. His works, such as The Hunt for Red October, Patriot Games, Clear and Present Danger, and The Sum of All Fears, have been turned into commercially successful films. His characters, most notably Jack Ryan, have been portrayed by actors like Alec Baldwin, Harrison Ford, Ben Affleck, Chris Pine, and John Krasinski. Another well-known character, John Clark, has been portrayed by Willem Dafoe, Liev Schreiber, and Michael B. Jordan.

Clancy's works have also inspired video games such as the Rainbow Six, Ghost Recon, Splinter Cell, and The Division series. He was a part-owner and Vice Chairman of Community Activities and Public Affairs of the Baltimore Orioles, a Major League Baseball team.