Short answers, pulled from the story.
Hermann Göring founded the Gestapo on the 26th of April 1933 by merging the political and intelligence sections of the Prussian police. The name came from a postal abbreviation of Geheime Staatspolizei coined by a post office clerk for a franking stamp.
Rudolf Diels was the first Gestapo chief, followed by Reinhard Heydrich from the 22nd of April 1934. Heinrich Müller became Gestapo chief in 1939 and held the post until the end of the war. Müller answered to Heydrich, Heydrich answered to Himmler, and Himmler answered only to Hitler.
By March 1937, the Gestapo employed an estimated 6,500 people across fifty-four regional offices. Despite its fearsome reputation, 80 percent of all Gestapo investigations were started from denunciations by ordinary German citizens, not from the Gestapo's own surveillance.
Adolf Eichmann's office within the Gestapo, Referat IV B4, coordinated the mass deportation of European Jews to the Nazi extermination camps. Gestapo chief Heinrich Müller also issued orders to the Einsatzgruppen and kept Hitler informed of the killing operations in the Soviet Union.
The International Military Tribunal at the Nuremberg trials declared the Gestapo a criminal organisation between 1945 and 1946. Several top Gestapo members were sentenced to death, but Gestapo chief Heinrich Müller disappeared at the end of the war and was never tried.
The Gestapo's Referat B1 placed agents in every diocese, obtained bishops' reports to the Vatican, and built networks to monitor ordinary clergy. Over 2,700 Catholic, Protestant, and Orthodox clergy were imprisoned at Dachau concentration camp alone.