There are still many unexplored aspects of World War II. One of them is the cooperation of foreign citizens with Nazi Germany and their service in various paramilitary auxiliary organizations of the Third Reich. The book draws a detailed and impartial picture of the service of foreigners in the army of the Third Reich, a comparative analysis of various categories of volunteers is carried out, internal political aspects that predetermined collaboration are considered, an attempt is made to assess the contribution of foreign citizens to the German military efforts and trace their post-war fate. The book is addressed to a wide range of readers interested in the history of World War II.