Tapping into phone calls is part of the history of telephone communication. The Ministry for State Security (MfS), despite an underdeveloped telephone network in the GDR, eagerly listened to and recorded telephone calls and used the information obtained for secret police and secret service activities. For this purpose, the State Security maintained its own departments which, on behalf of other MfS service units, specifically monitored telephone calls in the GDR, in the Federal Republic and also in cross-border telephone traffic. A historical study of the results of this wiretapping practice is very narrow for reasons of data protection. This book is the first to publish sources based on telephone surveillance measures. In addition to the scientific edition of around 150 sources, the historical context is examined, the value of the source is discussed and the listening practice and the consequences are presented in an essay from the perspective of contemporary witnesses. In addition, the technical working methods of the Stasi eavesdropping specialists are examined. The book thus introduces a group of sources that have not been known so far, provides new perspectives on the history of the SED dictatorship, the MfS and the opposition, and contains a variety of research suggestions.

Contributions by: Andreas Schmidt, Angela Schmole