Fun read. The CIA promotes an operational chief who suspects, pre-9/11, that Islamic terrorism is about to hit the fan. He wants to get more serious and aggressive with operations overseas. A secret program is developed to train an assassin. The company recruits a young man who lacks military training, but makes up for it through athleticism, confidence, and a desire for revenge (having been personally affected by the Lockerbie bombing). That young man is Mitch Rapp. He is trained by Hurley, an old-school piss-and-vinegar killer agent. 
 The first part of the book focuses on the training and initial hate-hate relationship between Hurley and Rapp. The boot camp style story with a crusty old drill sergeant is a bit familiar, almost cliched, but Flynn handles it very effectively and it's fun to read. 
 The second part deals with Rapp's first assignments--a series of interconnected hits designed to de-fund a terrorist operation. Hurley and Rapp target the Turkish arms dealer, a German banker who manages a terror group's numbered accounts, Lebanese torturers, and the terrorists' secretive Russian sponsors. Rapp has a problem following instructions, but ultimately the CIA gets what it wants--an agent ruthless and improvisational enough to do what needs to be done. The story is plausible, exhilarating, and shows off Rapp and Hurley's enormous talents.