Isabel Perón in the context of "Disappeared Detainees of the Dirty War"

The National Reorganization Process (Spanish: Proceso de Reorganización Nacional, PRN; often simply el Proceso, "the Process") was the military dictatorship that ruled Argentina from the coup d'état of March 24, 1976, until the unconditional transfer of power to a government elected by the citizens on December 10, 1983. In Argentina it is often known simply as the última junta militar ("last military junta"), última dictadura militar ("last military dictatorship"), última dictadura cívico-militar ("last civil–military dictatorship"), or última dictadura cívico-eclesial-militar ("last civil–clerical-military dictatorship") — because there have been several in the country's history and no others like it since it ended. It took the form of a bureaucratic-authoritarian state and was characterized by establishing a systematic plan of state terrorism, which included murders, kidnappings, torture, forced disappearances, and the kidnapping of babies (and concealment of their identity). It is considered "the bloodiest dictatorship in Argentine history".

The Argentine Armed Forces seized political power during the March 1976 coup against the presidency of Isabel Perón, the successor and widow of former President Juan Perón, at a time of growing economic and political instability. Congress was suspended, political parties were banned, civil rights were limited, and free market and deregulation policies were introduced. The President of Argentina and his ministers were appointed from military personnel while leftists and Peronists were persecuted. The junta launched the Dirty War, a campaign of state terrorism against opponents involving torture, extrajudicial murder and systematic forced disappearances. Public opposition due to civil rights abuses and inability to solve the worsening economic crisis in Argentina caused the junta to invade the Falkland Islands in April 1982. After starting and then losing the Falklands War against the United Kingdom in June, the junta began to collapse and finally relinquished power in 1983 with the election of President Raúl Alfonsín.

The clandestine detention, torture and extermination centers were secret facilities (ie, black sites) used by the Armed, Security and Police Forces of Argentina to torture, interrogate, rape, illegally detain and murder people. The first ones were installed in 1975, during the constitutional government of Isabel Perón. Their number and use became generalized after the coup d'état of March 24, 1976, when the National Reorganization Process took power, to execute the systematic plan of enforced disappearance of people during the Dirty War. With the fall of the dictatorship and the assumption of the democratic government of Raúl Alfonsín on December 10, 1983, the CCDs ceased to function, although there is evidence that some of them continued to operate during the first months of 1984.

The Armed Forces classified the CCDs into two types:

The Argentine Anticommunist Alliance (Spanish: Alianza Anticomunista Argentina, usually known as Triple A or AAA) was an Argentine fascist political paramilitary group operated by a sector of the Federal Police and the Argentine Armed Forces, linked with the anticommunist lodge Propaganda Due, that killed artists, priests, intellectuals, leftist politicians, students, historians and union members, as well as issuing threats and carrying out extrajudicial killings and forced disappearances during the presidencies of Juan Perón and Isabel Perón between 1973 and 1976. The group was responsible for the disappearance and death of between 700 and 1100 people.

The Triple A was secretly led by José López Rega, Minister of Social Welfare and personal secretary of Juan Perón. Rodolfo Almirón, arrested in Spain in 2006, was alleged to be his chief operating officer of the group, and was officially head of López Rega's and Isabel Perón's personal security. He was extradited from Spain in 2006 and prosecuted; he died in jail in June 2009. SIDE agent Anibal Gordon was another important member of the Triple A, although he always denied it. He was tried in Argentina in 1985 after the restoration of democracy and convicted in October 1986. Gordon died in prison of lung cancer the next year.