Tom Clancy, the best-selling author of fast-paced military thrillers including The Hunt for Red October and Clear and Present Danger, has died at a hospital in Baltimore, Maryland.
His publishers, the Penguin Group, did not disclose the cause of death.
Clancy, 66, sold some 50 million books over his three-decade writing career. Most famously, he created CIA analyst and later US president, Jack Ryan, who tackled Soviet submarines in Red October, Irish republican paramilitaries in Patriot Games, and a neo-Nazi nuclear plot in The Sum of All Fears.
Clancy's next novel, Command Authority, will be published in December. In the same month, his most celebrated character will appear again in cinemas in the blockbuster Jack Ryan: Shadow One, directed by Sir Kenneth Branagh and starring Chris Pine as the titular super-spy. Ryan has previously been portrayed on screen by Alec Baldwin, Harrison Ford and Ben Affleck.
Of Clancy's 28 books, 17 topped the New York Times bestsellers list. His writing also appeared in several videogames, after he co-founded the games company Red Storm Entertainment in 1996. Later bought by Ubisoft, the firm released several popular titles based on Clancy concepts, including Splinter Cell, Ghost Recon and Rainbow Six.
The author also became a part-owner of the Baltimore Orioles baseball team and in 2002 was 10th in the Forbes Celebrity 100 list, with annual earnings of $47.8m.
Born in Baltimore in April 1947, not far from the US Naval Academy at Annapolis, Clancy was reportedly fascinated by naval history and engineering as a boy. Any ambitions he had to join the military were thwarted, however, by his near-sightedness. Instead, he became an insurance salesman and poured his lifelong interests into his writing.
While researching his first novel, The Hunt for Red October, Clancy interviewed former submariners who worked at a Maryland nuclear power plant.
He submitted the manuscript to the Naval Institute Press, which had never released a novel, but agreed to pay him $5,000 to publish. When submarine officers checked the text, they found so few factual errors that they asked the author to cut around 100 pages of technical details.
Published in 1984, the book sold more than five million copies and was made into a 1990 film starring Baldwin and Sean Connery. Its popularity was boosted after a copy made its way to then-President Ronald Reagan, who described it as "my kind of yarn".
As well as his novels, Clancy co-wrote several non-fiction books about the US military's activities abroad, such as Into the Storm: On the Ground in Iraq and Every Man a Tiger: The Gulf War Air Campaign.
The access he was offered by his fans in the services informed many of the plots and details in his fiction, though he insisted that he never revealed any sensitive information about the operations of special forces he met.
Clancy said the key to his success as an author was simple graft. "You learn to write the same way you learn to play golf," he said.
"You do it, and keep doing it until you get it right. Writing isn't divinely inspired - it's hard work."
Update your news preferences and get the latest news delivered to your inbox.