The Ministry of State Security (MSS or Guóānbù; ; IPA: ) is the principal civilian intelligence, security and secret police agency of the People's Republic of China, responsible for counterintelligence, foreign intelligence and political security. The MSS is active in industrial espionage and adept at cyber espionage. Its military counterpart is the Intelligence Bureau of the Joint Staff Department. Described as one of the most secretive intelligence organizations in the world, it is headquartered in Beijing with subordinate branches at the provincial, city, municipality and township levels throughout China. Today's MSS began as the Chinese Communist Party's Central Special Branch until it was replaced by the Central Social Affairs Department (SAD) in 1936. In 1955, the Social Affairs Department was replaced by the Central Investigation Department (CID), China's primary civilian intelligence organization from 1955 to 1983 and the MSS's immediate predecessor. The MSS was created in 1983 with the merging of the CID and the counterintelligence elements of the Ministry of Public Security (MPS). Overview MSS functions as China's intelligence, security and secret police agency. A document from the U.S. Department of Justice described the agency as being like a combination of the Central Intelligence Agency (CIA) and Federal Bureau of Investigation (FBI). Author Clive Hamilton described it as being similar to an amalgamation of the Australian Security Intelligence Organisation (ASIO) and the Australian Secret Intelligence Service (ASIS) "with a lot more power and less subject to the constraints of the rule of law." The stated mission of the MSS is to ensure "the security of the country through effective measures against enemy agents, spies, and counter-revolutionary activities designed to sabotage, destabilize or overthrow China's socialist system." After the introduction of market elements in the Chinese economy in the early 1980s (leading to a hybrid economic system that includes Soviet-style economic planning and large-scale state ownership existing alongside a significant private sector) and especially after the end of the Cold War, many foreign analysts described the Communist "Party–State" and its security agencies as being left without a real ideology, relying only on repression and the stoking of Chinese nationalism; more recent works, however, highlight the increasing importance of Marxism–Leninism in the worldview, internal culture and self-image of the CCP security apparatus; Vladimir Lenin and Mao Zedong remain the central influences, although classical Chinese thinkers such as Sun Tzu are also studied. According to researchers Peter Mattis and Matthew Brazil, who