Three new books are to be published posthumously

He has sold more than 110 million books in 40 countries and 32 languages.

Born on 25 May 1927 in New York City, Ludlum was raised in Short Hills, New Jersey and left home as a teenager to pursue his acting career.

He studied at Wesleyan University, where he met his future wife, Mary Ryducha.

He acted in minor Broadway productions and television dramas in the 1950s before helping to launch the career of then-unknown actor Alan Alda when he produced The Owl and the Pussycat on a New Jersey stage in 1960.

He later said that his theatrical training helped him construct good book plots that the reader would enjoy.

Spy series

Other best-selling novels included The Osterman Weekend, The Matlock Paper, The Matarese Circle, The Parsifal Mosaic and The Apocalypse Watch.

His popular amnesiac spy, Jason Bourne, was a hit in the 1980s in a series of books including The Bourne Identity, The Bourne Supremacy and The Bourne Ultimatum.

The Bourne Identity is to hit the big screens later this year, with actor Matt Damon starring as the world-travelling adventurer.

Spies, government corruption and secrets were recurring themes in Ludlum's novels. He often took historical characters and built his novels around them.

The Chancellor Manuscript fictionalised the death of FBI head J Edgar Hoover and The Scarlatti Inheritance was about a group that financed Adolf Hitler's Third Reich.

Criticism

He was occasionally criticised for aping the styles of fellow thriller writers John Le Carre and Tom Clancy.

The Express newspaper "happily" noted the presence of Ludlum's trademark "ham-fisted cliches, risible dialogue and the scattergun use of italics and exclamation marks" in a recent book review.

"It's a lousy book. So I stayed up until 3am to finish it," wrote one reviewer in The Washington Post in a back-handed compliment.

His style, together with the ability to construct unexpected plot twists and exciting storylines, is the reason that many readers kept buying his books.

Big money deal

Publishers St Martin's Press lured him from his long-time publishers Bantam Books two years ago in a deal that was to earn the author $4m (�2.75m) per book, according to newspaper reports.

The Prometheus Deception was his latest novel - his 22nd - and was published in America last year. He wrote three more before his death, which will be published posthumously.

Ludlum also wrote under two pen names, Jonathan Ryder and Michael Shepherd.

He married Mary Ryducha in 1951, and they had two sons and a daughter. He kept two homes - in Connecticut and Naples, Florida, where he died.