Bestselling novelist Tom Clancy, best known for his intricate, compelling and plausible thrillers such as The Hunt for Red October and Patriot Games as well as for blockbuster video game franchises including Rainbow Six and Splinter Cell, has died at the age of 66.

Clancy died in a Baltimore hospital on Tuesday evening, according to his publisher. A cause of death has not been disclosed.

'People in the military said, "How did you get clearance for that? How did you know that?" He just knew a lot of stuff about everything.' -— Linwood Barclay on Tom Clancy

"He was a consummate author, creating the modern-day thriller, and was one of the most visionary storytellers of our time. I will miss him dearly and he will be missed by tens of millions of readers worldwide. I’m deeply saddened by Tom’s passing," said Penguin Group executive David Shanks, who was involved in the publication of each of Clancy’s books.

The Maryland author was best known for writing compelling, intricate and plausible spy and military-themed thrillers set during and after the Cold War.

"If you were a Clancy fan, if you picked up one of those books, you knew you were getting a lot of material," Canadian writer Linwood Barclay, known for his bestselling mystery thrillers, told CBC News today

Tom Clancy's novels include:

  • The Hunt for Red October (1984)
  • Red Storm Rising (1986)
  • Patriot Games (1987)
  • The Cardinal of the Kremlin (1988)
  • Clear and Present Danger (1989)
  • The Sum of All Fears (1991)
  • Without Remorse (1993)
  • Debt of Honor (1994)
  • Executive Orders (1996)
  • SSN (1996)
  • Rainbow Six (1998)
  • The Bear and the Dragon (2000)
  • Red Rabbit (2002)
  • The Teeth of the Tiger (2003)
  • Dead or Alive (2010)
  • Against All Enemies (2011)
  • Locked On (2011)
  • Threat Vector (2012)
  • Command Authority (2013)

"You were getting a great thriller. You were getting all this tremendous detail, this kind of insight into CIA operations and the military.… You weren't just getting a thrill ride, you were getting immersed in all this technical information, the kind of stuff you weren't going to find out from a great many authors.

"When [Clancy] made reference to submarine details, people in the military said, 'How did you get clearance for that? How did you know that?' He just knew a lot of stuff about everything, from weaponry to battleships to whatever it was. He was famous for taking that kind of detail and putting it in his novels … nobody just pulled a gun on somebody [in his books] — it was a five-page description of the gun. He loved that kind of detail."

Clancy, who was also a co-owner of Major League Baseball's Baltimore Orioles, said he thought of himself as "a storyteller" first and foremost.

"I think about the characters I've created, and then I sit down and start typing and see what they will do. There's a lot of subconscious thought that goes on. It amazes me to find out, a few chapters later, why I put someone in a certain place when I did. It's spooky," he once told an interviewer.

Born Thomas Leo Clancy Jr. in Baltimore in 1947, the lifelong military enthusiast initially worked in the insurance industry, but long hankered to write novels based on the armed forces. He never served in the military (save for some ROTC classes in college) due to his near-sightedness, which kept him from active duty.

Reading Tom Clancy

Airman Tony Strader of the 621st Air Mobility Squadron at McGuire Air Force Base, N.J., is seen reading a Tom Clancy thriller between aircraft arrivals at Rinas Airport in 1999. (Reuters)

Clancy's debut, The Hunt for Red October, emerged in 1984 after Clancy sold his manuscript to the Naval Institute Press for about $5,000 US. It marked the publisher's first foray into original fiction.

Based on a real-life 1975 incident in which a Soviet missile frigate attempted to defect, The Hunt for Red October introduced the world to Jack Ryan (though the ship didn't make it in real life, the attempt is successful in Clancy's book). The fictional hero would eventually star in many of Clancy's novels, including Patriot Games, The Sum of All Fears, and Clear and Present Danger.

A president's approval

Tom Clancy

Author Tom Clancy's attention to technical detail helped win over readers and earned him the respect of the intelligence and military community. ( Brendan Smialowski/Getty Images)

Even former U.S. president Ronald Reagan was a fan, praising The Hunt for Red October during the mid-1980s and telling reporters that it was "a really good yarn." That endorsement helped vault the book to the top of the New York Times bestseller list.

Many of Clancy's more than two dozen books inspired film and television adaptations, with Alec Baldwin, Harrison Ford and Ben Affleck among those to portray Clancy's iconic Jack Ryan character.

The latest Jack Ryan movie is slated to open on Dec. 25, with Chris Pine, Keira Knightley and Kevin Costner starring in the Kenneth Branagh-directed Jack Ryan. Meanwhile, Clancy had been set to publish the new novel Command Authority (co-written with Mark Greaney) in early December. It will mark his final book, after a career of international sales his publisher estimates at more than 100 million copies.

Films based on Clancy novels include:

  • The Hunt for Red October (1990), starring Sean Connery and Alec Baldwin.
  • Patriot Games (1992), starring Harrison Ford.
  • Clear and Present Danger (1994), starring Harrison Ford and Willem Dafoe.
  • NetForce (1999), a TV movie starring Scott Bakula.
  • The Sum of All Fears (2002), starring Ben Affleck and Morgan Freeman.

A regular name atop bestseller lists, Clancy also wrote military history, biographies and other non-fiction books — genres that helped make him a favourite of U.S. military and intelligence staffers.

He extended his appeal into a new generation with his work crafting stories for video games, including blockbuster franchises like Splinter Cell, Rainbow Six and Ghost Recon.

In the mid-1990s, he helped found Red Storm Entertainment, which released games — some based on his books, others on original ideas. Red Storm was later purchased by gaming giant Ubisoft, which continues to create games under the Clancy moniker.

"We are saddened to learn of Tom Clancy's passing and our condolences go out to his family. Tom Clancy was an extraordinary author with a gift for creating detailed, engrossing fictional stories that captivated audiences around the world," Ubisoft said in a statement.

"The teams at Ubisoft, especially at the Red Storm studio, are incredibly grateful to have collaborated with and learned from him."

Clancy is survived by his second wife, Alexandra Marie Llewellyn, and five children, according to his publisher. No details were forthcoming about funeral arrangements.

With files from The Associated Press