From Berlin to Bucharest, from Warsaw to Sofia, Soviet tanks crossed national borders across East Central Europe at the end of the Second World War. The arrival of the Red Army marked an important turn in history. Within only a few years, the often unpopular communist parties developed into political organizations with mass followings. They managed to seize power, eliminate political opposition to their rule, and purge the state apparatus of undesirable personnel. In Securing the Communist State, Liesbeth van de Grift provides a new understanding of these organizations using recently disclosed material from the communist archives in Berlin and Bucharest. She reveals how these communist parties gained control over the security apparatus after 1945 in East Central Europe from a transitional justice perspective, focusing on purges and personnel policies. This book shows that the personal break after 1945 was not as radical as is often thought.