Robert Ludlum's the Bourne Objective

Readers were first introduced to Jason Bourne's nemesis Leonid Arkadin, a brilliant Russian assassin and fearless international mercenary, in THE BOURNE SANCTION. His girlfriend was killed during a fight for which an enraged Arkadin blames Bourne. In THE BOURNE DECEPTION, Arkadin hunted Bourne to take revenge and kill him. Bourne, in a fight for his life, learned that Arkadin's skills mirror Jason's because he received the same original CIA Treadstone training.