Tom Clancy, the best-selling author of techno-thrillers Clear and Present Danger and Patriot Games, died last night in a Baltimore hospital at the age of 66, his publisher has confirmed. Clancy was best known for creating the iconic character Jack Ryan and for the startling authenticity he gave to descriptions of military technology and strategy.

Clancy launched his writing career with The Hunt for Red October in 1984, which garnered a positive review from President Ronald Reagan (who called it a “perfect yarn”). By the time his second novel Red Storm Rising was released in 1986, some military officials suspected that Clancy had gained access to classified information on weaponry, but in fact, he had just pieced together the information through extensive research and informed guesswork. The author was also noted for his “Guided Tour” nonfiction series that explored military machinery in detail.

In addition to his popular novels and spin-off series, Clancy’s work made its way to the big screen in a number of high-profile projects. CIA analyst Jack Ryan, the central character in Clancy’s most popular works, has been portrayed by big-name stars: Alec Baldwin in the 1990 film version of Red October; Harrison Ford in 1992’s Patriot Games and 1996’s Clear and Present Danger; and Ben Affleck in the 2002 film The Sum of All Fears. A fifth film Jack Ryan: Shadow One is slated for release this year with Chris Pine in the titular role.

“Spending time with Tom prior to shooting was the best part of that whole experience for me,” says Baldwin, the first Jack Ryan, in a statement to EW. “Tom was smart, a great story teller and a real gentleman.”

Penguin Group (USA)’s executive David Shanks, who was involved in the publication of every Clancy book, said in a statement, “I’m deeply saddened by Tom’s passing. 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.”

Ivan Held, President and Publisher of G.P. Putnam’s Sons says, “It was an honor to know Tom Clancy and to work on his fantastic books. He was ahead of the news curve and sometimes frighteningly prescient. To publish a Tom Clancy book was a thrill every time. He will be missed by everyone at Putnam and Berkley, and by his fans all over the world.