Four former commandos break into a shabby little town controlled by the local mafia, with the goal of avenging their friend’s death. In the space of a few weeks, the town is turned into a terrifying spectacle featuring invisible “performers” who carry out audacious kidnappings of racketeers and armed raids on gambling establishments… Walter Wayger’s novel “Operation ‘Hammer’” became a bestseller in the United States—it is both a gangster adventure action thriller and an ironic parody of it.