Journalist, publicist and author, Rainer Rupp is an expert on U.S. foreign policy and military strategy of NATO and the U.S.. He writes for the newspapers junge Welt and Neues Deutschland.
He worked under the codenames Mosel and later Topaz for the East German intelligence service HVA (General Reconnaissance Administration) in the NATO headquarters in Brussels from 1977 until 1989, releasing documents of the highest importance (Cosmic Top Secret) to the Eastern Bloc.
He was sentenced to twelve years in prison for treason in 1994 and was released early in July 2000. Rupp became a member of the left party PDS and served temporarily as an advisor in regard to issues of security and foreign policy; he quit the party, however, in 2003.
Rainer Rupp (mit Karl Rehbaum und Klaus Eichner): Militärspionage: die DDR-Aufklärung in NATO und Bundeswehr. Edition Ost, Berlin, 2011, ISBN 978-3-360-01828-1.
Klaus Eichner, Karl Rehbaum: Deckname Topas. Der Spion Rainer Rupp in Selbstzeugnissen, edition ost, Berlin, 2013, ISBN 978-3-360-01846-5.