Jack Mandelbaum (born April 10, 1927 as Janek Mandelbaum) is a Holocaust survivor from the Free City of Danzig. His experiences as a boy during World War II were the subject of 's children's book of Mandelbaum surviving in a concentration camp separated from his family: Surviving Hitler: A Boy in the Nazi Death Camps. Mandelbaum was in many different concentration camps; he considered Gross-Rosen to be the worst of them.