In this book, we follow the political, economic, and armed collaboration with the conqueror, as it manifested in the region of Attica. Through the study of archives that are being made public for the first time, the actions of those who collaborated are described, the reasons and mechanisms of the development of the phenomenon of collaboration are examined, as well as the political and economic conditions that favored its appearance. The policies followed by the three Greek occupation governments, the role of traders, industrialists, political engineers, and others in economic transactions with the conquerors, the actions of the Greek Royal Guard, the Security Battalions, the Greek agents of the SS and others, who formed the armed part of the collaboration, and their judicial treatment after the end of the occupation, are at the center of this study. br Collaboration with the conqueror characterized everyday life throughout occupied Europe. Politicians, military personnel, entrepreneurs, mayors, judges, priests, journalists, collaborated closely with the occupation authorities, for many and different reasons. The initially apparent victory of Germany in the war, anti-communism, the acquisition of quick and easy wealth, ideological identification with Nazi Germany and fascist Italy, the need for survival, were some of them. In Greece, although 80 whole years have passed since the end of the occupation, the issue of collaboration with the conqueror continues to be a taboo subject. This is the result of the political amnesia followed by all post-war governments, in their attempt to manage the political consequences of the unprecedented, in intensity and extent, collective trauma caused to Greek society by collaboration. Collaboration with the conqueror was the starting point of the new division, which, with the contribution of other factors, led to the civil conflicts of the occupation, the December events, and finally to the civil war of the 1940s.