Ruth Berlau was born in Charlottenlund, a suburb of Copenhagen, the daughter of a merchant. She attended a Catholic convent school but dropped out at age of 13, following her parents' divorce. She went to work as a sales clerk and a dentist's assistant to support herself, her mother and sister. She also took acting lessons at the Forsogsscenen (Experimental Theater) in Copenhagen. In 1928, she married Robert Lund, a doctor. The couple traveled extensively throughout Europe. She visited the Soviet Union on a bicycle and reporting tour in 1930 and joined the Danish Communist Party. That same year she made her stage debut in the role of Anna in Bertolt Brecht's Drums in the Night. She achieved her great ambition to become an actress with the Royal Theater of Copenhagen. She also became a co-founder of the Revolutionaert Teater, where she directed some plays. In 1936, she divorced her husband and became a secretary, translator, and collaborator of Brecht. Together they published the short story collection Jedes Tier kann es, considered obscene at the time. She and Brecht became lovers, and in 1940 she followed him to the USA, where she systematically photographed all his productions. In 1944, she gave birth to her only child, a premature baby who died after only a few days. After World War II, Ruth followed Brecht to East Germany. Her memoirs, entitled Living for Brecht, revealed details of their 21-year relationship as well as her own life of extremes. She died after setting her bed on fire with a cigarette.