In the April issue of Vanity Fair, William Langewiesche embeds with warrior/investigators from G4S, the worldís third-largest private-sector employerómen and women overseas who are keeping you safe, even if you donít know it. In this excerpt from his profile of G4S, Langewiesche watches as contractors from the security behemoth clean up after an explosion in a crowded souk in South Sudanóand learns that even small victories, in the face of horror, can be cause for encouragement.