Helen Rosenau was born in Monte Carlo, Monaco, and grew up there and in Bad Kissingen, Germany. Her parents were Albert Rosenau, a physician, and his wife Klara. She was educated privately and passed the Abitur (university-prep exam) in 1923.
She studied art history at the universities of Munich, Halle, Berlin, Bonn and Hamburg. In 1930, she completed her studies with art historian Erwin Panofsky in Hamburg, with a dissertation on the architectural history and importance of Cologne Cathedral.
After the Nazis rose to power in Germany, her career was blocked due to her Jewish descent, and she went to Switzerland to continue her research on the medieval Grossmünster church in Zurich. In 1933, she arrived in Great Britain, where she was supported by a grant from the British Federation of University Women. She earned a Ph.D. in art history at the Courtauld Institute in London and published her thesis under the title Design and Medieval Architecture (1934).
From 1941, she worked as an associate of the London School of Economics, giving adult education lectures and courses in German. At the end of World War II, she became a naturalized British citizen.
From 1947 to 1951, she taught at the University of London, then moved to the University of Manchester. From 1968 she taught again at the University of London and also at the Leo Baeck College.
Dr. Rosenau wrote numerous scholarly articles and books in her fields of interest, which ranged from medieval cathedrals and architecture to Jewish art and architecture, sociology of art, French revolutionary architecture, and utopian architecture and urban planning. These included The Ideal City: Its Architectural Evolution (1959) and Vision of the Temple: The Image of the Temple of Jerusalem in Judaism and Christianity (1979).