Reign in Blood is the third studio album by American thrash metal band Slayer, released on October 7, 1986, by Def Jam Recordings. The album was the band's first collaboration with producer Rick Rubin, whose input helped the band's sound evolve. The release date of the album was delayed because of concerns regarding the lyrical subject matter of the opening track "Angel of Death", which refers to Josef Mengele and describes acts such as human experimentation that he committed at the Auschwitz concentration camp. The band's members stated that they did not condone Nazism and were merely interested in the subject.