Josef Mengele (16 March 1911 – 7 February 1979) was a German SS officer and a physician in the Nazi concentration camp Auschwitz-Birkenau. He gained notoriety for being one of the SS physicians who supervised the selection of arriving transports of prisoners, determining who was to be killed and who was to become a forced laborer, and for performing human experiments on camp inmates, amongst whom Mengele was known as the Angel of Death.
In 1940, he was placed in the reserve medical corps, following which he served with the 5th SS Panzergrenadier Division Wiking. In 1942, he was wounded at the Russian front and was pronounced medically unfit for combat, and was then promoted to the rank of SS-Hauptsturmführer (Captain). After the war, he became one of the most hunted of Nazi war criminals.
In 1943, Mengele replaced another doctor who had fallen ill at the Nazi extermination camp Birkenau. On May 24, 1943, he became medical officer of Auschwitz-Birkenau's "Gypsy camp". In August 1944, this camp was liquidated and all its inmates gassed. Subsequently Mengele became Chief Medical Officer of the main infirmary camp at Birkenau. He was not, though, the Chief Medical Officer of Auschwitz — superior to him was SS-Standortarzt (garrison physician) Eduard Wirths.