The Main Directorate of State Security was the name of the Soviet Union's most important security body within the People's Commissariat of Internal Affairs NKVD USSR. At the time of its existence, which was from July 10, 1934 to February 3, 1941, the GUGB reflected exactly the Secret Operational Directorate within OGPU under the Council of People's Commissars, which operated within OGPU structure from 1923 to 1931/32. An intelligence service and secret police from July 1934 to February 1941, it was run under the auspices of the Peoples Commissariat of Internal Affairs (NKVD). Its first head was first deputy of People's Commissar of Internal Affairs, Commissioner 1st rank of State Security Yakov Agranov.