Short answers, pulled from the story.
SAVAK was established in Tehran in 1957 by national security law. It was dissolved in 1979 by Iranian Prime Minister Shapour Bakhtiar, shortly before the fall of the Pahlavi monarchy during the Iranian Revolution.
The CIA played a significant role in establishing SAVAK, providing both funding and training. A U.S. Army colonel arrived in Persia in September 1953 to build the initial intelligence nucleus, followed by a five-person CIA team including Major General Herbert Norman Schwarzkopf, who trained nearly all of SAVAK's first generation of personnel. The French intelligence service SDECE also provided training in surveillance and interrogation during the mid-1950s and early 1960s.
Estimates vary widely and were disputed even during SAVAK's operation. Scholar Gholam Reza Afkhami estimated 4,000 to 6,000 members, while Time magazine reported 5,000 in a February 1979 publication. After 1963, the Shah expanded SAVAK to over 5,300 full-time agents plus an unknown number of part-time informers. Historians have offered figures ranging from 6,000 to 60,000.
According to historian Ervand Abrahamian, SAVAK used bastinado, sleep deprivation, nail extractions, electrical shocks, cigarette burns, acid dripped into nostrils, near-drowning, and mock executions. An electric chair fitted with a metal mask to amplify screams for the prisoner was nicknamed the Apollo, after the American spacecraft. The Federation of American Scientists documented additional methods including the insertion of broken glass into the rectum and the use of weights attached to the testicles.
SAVAK was formally dissolved by Prime Minister Shapour Bakhtiar in 1979, and many of its officials were executed after the revolution. However, according to author Charles Kurzman, the organization was never truly dismantled. It continued under a new name, SAVAMA, formally known as the Ministry of Intelligence and National Security of Iran, with the same codes of operation and a relatively unchanged staff.
General Teymur Bakhtiar, the first director, was dismissed in 1961 and later assassinated by SAVAK agents in 1970. General Hassan Pakravan led the agency from 1961 to 1966 and was executed by the Khomeini regime after the revolution. General Nematollah Nassiri replaced Pakravan in 1966 and was also executed after the revolution. Hossein Fardoust, a former classmate of the Shah who served as deputy director, switched sides during the revolution and helped preserve the bulk of the SAVAK organization.