From the author's bio: "Mark Greaney has a degree in international relations and political science and is pursuing his masters in intelligence studies with a concentration in criminal intelligence. He speaks Spanish and German. In researching, The Gray Man he trained extensively alongside military and law enforcement personnel in the use of firearms, battlefield medicine and close-range combative tactics." 
 Two possibilities spring to mind after reading that. Either Greaney is the biggest liar and fraud since James Frey, or he is fully capable of tracking down and killing anyone who gives his book a bad review. I'm going to play it safe and give this one a thumbs up. 
 If Brad Pitt and Angelina Jolie's characters in Mr. & Mrs. Smith had a baby boy, and his godfathers were Rambo and Jason Bourne, I'm pretty sure that he would have grown up to be Courtland Gentry. Gentry is a hit man/ mercenary known as the Gray Man in intelligence circles who only targets the worst of international criminals if the price is right. A former CIA operative who was burned, he now does dirty jobs for Sir Donald Fitzroy's private security firm. 
 Gentry has just pulled off a hit in the Mid-East and is in the midst of escaping through Iraq when Fitzroy is approached by a lawyer named Lloyd who represents a powerful international corporation. It turns out that the Gray Man's latest target was the brother of an African despot that Lloyd's corporation needs to complete a deal worth billions, but the dictator's price is the death of the Gentry. Fitzroy's family is threatened, and he's blackmailed into betraying the Gray Man. 
 But Gentry is remarkably hard to kill and Lloyd's corporation brings in their own security expert to flush him out. Exhausted and injured, Gentry is hounded and herded across Europe by numerous international hit teams brought in with the promise of a giant payday for whoever finally kills the Gray Man. 
 This obviously isn't going to be winning a National Book Award, but if you're in the mood for a fast-paced action-adventure story with a stone cold bad-ass fighting his way across the Mid-East and Europe, then there's a lot of fun to be had with this book. Greaney manages to bring an arsenal's worth of modern weapons into the story without letting it devolve into gun pornography. There's a lot of action cliches here, but the story has enough momentum to make you forgive them. 
 There's your good review. Please don't kill me, Mr. Greaney...