The Nazis' vast concentration camp network and, later, the 'Final Solution' programme made heavy demands on the SS whose responsibility it was. The use of 'overseers' minimised costs and enabled the camps to run with fewer SS personnel. As this well researched book describes, there were three principal groups of 'helpers': Sonderkommandos, Kapos and Trawniki.The Sonderkommandos' duties included unloading Jews from trains, collecting their possessions and allocating work details. Under SS supervision, they also ran the gas chambers and crematoria.The Kapos oversaw the Sonderkommandos. Many were originally prisoner functionaries recruited from violent criminal gangs and had a well-deserved reputation for brutality.The third group, known as Trawniki or Trawnikimanner, were Central and Eastern European collaborators recruited from Russian POW camps. While some served in a military capacity, others played an instrumental role in the Holocaust programme, rounding up and transporting Jews from the ghettos to the concentration camps.The graphic images and text of this Images of War series work demonstrate that the 'overseer' system was extensive and effective as its members competed without scruple to maintain the favour of their SS masters while pitting victim against victim.