Ruth Gruber was born on September 30, 1911, in Brooklyn, the fourth of five children of David and Gussie (Rockower) Gruber, Russian Jewish immigrants who owned a wholesale and retail liquor store and later went into real estate. She graduated from New York University at age eighteen and in 1930 won a fellowship to the University of Wisconsin, where she received her M.A. in German and English literature. In 1931, Gruber received a fellowship from the Institute of International Education for study in Cologne, Germany. Her parents pleaded with her not to go: Hitler was coming to power. Nevertheless, she went to Cologne and took courses in German philosophy, modern English literature, and art history. She also attended Nazi rallies, her American passport in her purse, a tiny American flag on her lapel. She listened, appalled, as Hitler ranted hysterically against Americans and even more hysterically against Jews.