Robert Ludlum's The Bourne Sanction

For university professor David Webb — forever caught between two identities — life can never be ordinary. Lately he seems to have found some well-earned normality. But David is still haunted by the splintered nightmares his former life — as Jason Bourne. Soon he finds himself embroiled in a Central Intelligence operation to hunt down a terrorist organisation planning a major attack, and is plunged into the deadliest and most tangled assignment of his double life — and the murky underworld he's been trying to escape. With his own side trying to take him down, all the while an assassin as brilliant and damaged as himself is getting closer by the minute...