The Gray Man - Mark Greaney

To those who lurk in the shadows, he's known as the Gray Man. He is a legend in the covert realm, moving silently from job to job, accomplishing the impossible and then fading away. And he always hits his target.But there are forces more lethal than Gentry in the world. Forces like money. And power. And there are men who hold these as the only currency worth fighting for. In their eyes, Gentry has just outlived his usefulness.But Court Gentry is going to prove that, for him, there's no grey area between killing for a living and killing to stay alive...