This book is dedicated to the 100th anniversary of the formation of the Special Departments of the Cheka-KGB-FSB (1918-2018). The author of the book briefly tells about the main stages of the development and formation of military counterintelligence in Russia. For the first time, archival materials were introduced into historical circulation, shedding light on the activities of military counterintelligence during the Great Patriotic War. The book is intended for historians, political scientists, student youth, all those who are not indifferent to the history of domestic special services.