John le Carré, author of highly acclaimed espionage novels including The Night Manager, The Little Drummer Girl, and Tinker Tailor Soldier Spy, has passed away at age 89.

The author, whose real name was David Cornwell, died of pneumonia Saturday night following a short illness, the BBC reports. "We all grieve deeply his passing. Our thanks go to the wonderful NHS team at the Royal Cornwall Hospital in Truro for the care and compassion that he was shown throughout his stay. We know they share our sadness," his family said in a statement.

Cornwell worked for the U.K.'s Security Service (MI5) and Secret Intelligence Service (MI6) in the '50s and '60s before his third novel, 1963's The Spy Who Came in from the Cold, became an international bestseller and he left to focus on his writing.

He went on to write a string of bestselling novels including 1974's Tinker Tailor Soldier Spy, which was adapted into a 1979 BBC miniseries starring Alec Guinness and then a 2011 film with Gary Oldman, Benedict Cumberbatch, and Tom Hardy.

Many of his other novels were adapted for film and TV, including 2001's The Constant Gardener, which became an acclaimed movie starring Ralph Fiennes and Rachel Weisz.

More recently, AMC and BBC One adapted 1993's The Night Manager into an Emmy and Golden Globe-winning miniseries starring Tom Hiddleston, Olivia Colman, and Hugh Laurie. Watch le Carré reveal the real-life inspiration behind Laurie's character below, and watch more of his behind-the-scenes insights over at AMC Talk.

The two networks also teamed up to adapt le Carré's 1983 novel The Little Drummer Girl into a 2018 miniseries with Michael Shannon, Florence Pugh, and Alexander Skarsgård. Le Carré served as an executive producer on both series.

His final novel, Agent Running in the Field, was published last year.

Paying tribute to le Carré on Twitter, fellow author Stephen King wrote: "John le Carré has passed at the age of 89. This terrible year has claimed a literary giant and a humanitarian spirit."

David Cornwell a.k.a John le Carré is survived by Valerie, his wife of 48 years, and four sons.

Rest in Peace – and thank you for your contribution.