Vladimir Putin is the current President of Russia and former KGB Lieutenant Colonel. He operated within the KGB from 1975 and resigned during the 1991 Coup against Mikhail Gorbachev.
Vadim Bakatin was a Soviet politician who served as the last chairman of the KGB in 1991. He is the last surviving former chairman of this organization. He was appointed to dismantle the KGB, but he was unable to control this organization and to fulfill the task. Boris Yeltsin absolved the KGB into other administrations.
It discredited the CIA, which had assured the government that the Soviet Union would take at least eight years to make its own bomb. It discredited the FBI, which had failed to uncover the Soviet atomic spy ring until it was too late. It broke the special relationship between the United States and Britain because Klaus Fuchs, the spy blamed for the theft had been sent to Los Alamos by the British. It ended all possibility of a free international exchange of atomic knowledge. It destroyed American innocence when it became apparent that American citizens could be ideological spies, and it ushered in the McCarthy era.
The theft of America's atom bomb secrets was the KGB's greatest coup. It made no difference to the balance of atomic terror--the Soviet Union would have developed its own bomb sooner or later anyway--but it changed the course of American social history.
In addition, the KGB managed internal counterintelligence and international espionage for the Soviet Union. Crimes against the state such as treason were also handled by the agency, which conducted extensive investigations of many Russian citizens. The size and scope of the KGB made it into an extremely powerful organization, which ended up being its downfall in 1991 when Mikhail Gorbachev decided that it had too much power and it needed to be reorganized.
The KGB had several missions. One of the primary missions of the intelligence organization was the protection of the Soviet state, through the ruthless prosecution of dissidents and enforcement of border security. The organization arose from earlier groups that had managed prison camps, and it adopted some brutal interrogation tactics and police practices in an effort to keep social unrest to a minimum. KGB border guards also protected the integrity of the state by restricting access to the Soviet Union and keeping an eye on people leaving it, as well.
In 1953, the ambitious Lavrentiy Beria consolidated the MVD (Russian Ministry of Internal Affairs) and the MGB into an enlarged MVD. In 1954, a year after his execution, his MVD monolith became two agencies — the MVD (secret police) and the KGB (espionage), answerable only to the Council of Ministers about intelligence and national security. In 1978, the KGB was re-named KGB of the Soviet Union (USSR KGB), and its Chairman was a council minister. Besides being the Union’s KGB, it was the republican KGB for Russia proper.
The KGB originated as the Cheka (Chrezvychainaya Komissiya po Borbe s Kontr-revolutisnei i Sabotazzhem – Extraordinary Commission for Combating Counter-Revolutions and Sabotage) established 20 December 1917, headed by Felix Dzerzhinsky, and based upon the Tsarist Okhrana intelligence-security agency; Cheka (Extraordinary Committee) derives from the two initial letters of each word in Chrezvychainaya Komissiya, and its agents are Chekists (Chekisty).  To protect Soviet national security, the Cheka (1917–22) often changed name and structure — becoming, among others, the State Political Directorate (OGPU) in 1923; the People’s Commissariat for State Security (NKGB) in 1941; and and the Ministry for State Security (MGB) in 1946, yet always remained the Cheka, the Sword and Shield of the USSR.
Komitet Gosudarstvennoy Bezopasnosti (KGB) is a Russian language abbreviation. In English it means State Security Committee. This agency evolved from the soviet secret police and had many name and organizational changes before it was named KGB. Its first name was cheka created on December 10, 1917. Feliks Edmundovich Dzerzhinsky was the first head of Cheka.
The Russian KGB was an umbrella organization of USSR up till November 6, 1991. Russias main intelligence agency, its security agency and the secret police, all came under the KGB.