The main focus is on war criminals Josef Mengele, the physician who conducted medical experiments at Auschwitz concentration camp; Martin Bormann, Adolf Hitler's personal secretary; Klaus Barbie, known as the "Butcher of Lyon"; and Adolf Eichmann, one of the major organizers of the Holocaust.

Other former SS members include, Obersturmbannführer Otto Skorzeny and Elfriede Rinkel, who was a guard at Ravensbrück, the Nazis' largest concentration camp for women.

USA Today gave the book two out of four stars and said, "There's nothing particularly new here about the search for Adolf Hitler's most notorious henchmen and women," but, it'll "no doubt, be a welcome addition to the best-selling series.

"[2] As of October 22, 2018, Killing the SS was among Amazon's best sellers and at number one on the New York Times list of best-selling nonfiction.

It also held the number one spot on the New York Times Combined Print & E-Book Nonfiction list.