This book is about how Latvia, Lithuania and Estonia became the “Soviet Baltic States” - about the decision-making mechanisms for the Sovietization of the Baltic republics and about the people who stood behind these decisions. When did Stalin conceive the idea of the Baltic Sovietization project? How did the methods of incorporating the Baltic states into the Soviet system change? How were the relations between the Kremlin, representatives of the Baltic elites and the population? The answers to these and many other questions are provided by new documents from the federal archives of Russia, on which this research is based. The book is intended for a wide range of readers.