Covert-One series
Written by other authors, supposedly based on unpublished material by Robert Ludlum.

The Hades Factor (by Gayle Lynds) (2000)
The Cassandra Compact (by Phillip Shelby) (2001)
The Paris Option (by Gayle Lynds) (2002)
The Altman Code (by Gayle Lynds) (2003)
The Lazarus Vendetta (by Patrick Larkin) (2004)
The Moscow Vector (by Patrick Larkin) (2005)
The Arctic Event (by James H. Cobb) (2007)

Robert Ludlum was the author of twenty-one novels, each one a New York Times bestseller. There are more than 210 million of his books in print, and they have been translated into thirty-two languages. He is the author of The Scarlatti Inheritance, The Chancellor Manuscript, and the Jason Bourne series--The Bourne Identity, The Bourne Supremacy, and The Bourne Ultimatum--among others. Mr. Ludlum passed away in March, 2001.