One of its main tasks was spying on the population, mainly through a vast network of citizens turned informants, and fighting any opposition by overt and covert measures, including hidden psychological destruction of dissidents (Zersetzung, literally meaning decomposition). Its Main Directorate for Reconnaissance (German: Hauptverwaltung Aufklärung) was responsible for both espionage and for conducting covert operations in foreign countries. Under its long-time head Markus Wolf, it gained a reputation as one of the most effective intelligence agencies of the Cold War. Numerous Stasi officials were prosecuted for their crimes after 1990. After German reunification, the surveillance files that the Stasi had maintained on millions of East Germans were laid open, so that any citizen could inspect their personal file on request; these files are now maintained by the Federal Commissioner for the Stasi Records.