Robert Ludlum's The Bourne Sanction by Eric Van Lustbader
For Jason Bourne, forever caught between two identities - mild-mannered linguist David Webb and lethal super-spy - life can never be ordinary. But when his old mentor, Professor Spector, installs him as head of the comparative linguists department at Georgetown University, it seems he may have found a measure of normalcy at last. Until a hitherto unknown terrorist organisation comes up on Central Intelligence radar, with a plan to execute a major attack on the east coast of the United States within a week. Without sufficient hard intelligence to back them up and with competing intelligence organisations keen to undermine new director of Central Intelligence Veronica Hart, they have no choice but to employ a rogue agent capable of hunting down a shadowy terrorist mastermind on his own - Jason Bourne. Suddenly Bourne is plunged into the deadliest and most tangled operation of his double life: pursuing the head of the Black Legion - a murderous terror group with its roots in the darkest days of World War II - while his own side tries to take him down, and all the while an assassin as brilliant and damaged as himself is getting closer by the minute