Sylvia Horwitz, née Laibman, was born in New Castle, Pennsylvania, and grew up in Cleveland, Ohio. She graduated from Case Western University in 1932 and moved to New York City, where she worked as a copywriter and as a teacher at the New School for Social Research. She married Louis Horwitz, a social worker, with whom she had a son. In 1945, at the end of World War II, her husband was working with the United Nations Relief and Rehabilitation Agency to resettle refugees in Europe, and she got on one of the first ships of American civilians allowed to join their spouses there. In Rome, when she found that there was no school for English-speaking children, she helped start the Overseas School of Rome and served as its first director. Her stay in Rome also sparked an interest in art and archeology that eventually led to her books Toulouse-Lautrec: His World (1973), Francisco Goya: Painter of Kings and Demons (1974), and The Find of a Lifetime: Sir Arthur Evans and the Discovery of Knossos (1980).