Esther Rosencrantz was born in San Francisco, November 18, 1876. She received her undergraduate education at Leland Stanford Junior University, graduating A.B. in 1899. She attended medical school at Johns Hopkins University, from which she received her MD in 1904, being the first woman from California to receive a medical degree from Hopkins. While at Hopkins, Dr. Rosencrantz studied under the great four: Welch, Kelly, Halsted and Osler. The last, Dr. William Osler created such an impression on Dr. Rosencrantz that throughout her life she collected any materials by or about Dr. Osler that she could buy, exchange or coax from other collectors. Her collection, now part of the Special Collections Division at UCSF, is perhaps the most comprehensive (up to the time of her death in 1950), outside of that at the Osler Library at McGill University in Montreal, Quebec.

Dr. Rosencrantz's strong interest in chest diseases, and tuberculosis in particular, also dates from the time of her work with Dr. osler. Following graduation in 1904, she worked at a number of medical/research institutions in this country and abroad, including the New York Infirmary for Women; Brompton Hospital for Consumption, London; the Charité Hospital, Berlin; the Pasteur Institute, Paris and Lille, with Calmette; the Insel Spital, Berne, where she worked under Sahli, and the Tuberculosis Division of the Dept. of Public Health, New York City.

In 1913 she returned to California to become a member of the Medical Staff at UCSF, where she was also attending physician at the San Francisco Hospital, in charge of the University of California tuberculosis wards until 1937.

After World War I Dr. Rosencrantz went to Italy as a member of the Tuberculosis Division of the Red Cross Commission, and was decorated by the Italian and U.S. governments for her work there. Among her responsibilities in California were membership in the Advisory Board of the Arequipa Sanitarium; consultant in the San Luis Obispo County Tuberculosis Department; consultant for the Tuberculosis section of the Hassler Health Home. Dr. Rosencrantz was also a member of the AAAS, the American Sanitorium Association, the American Trudeau Society, the Pasteur Society of Northern California, the International Association against Tuberculosis, the American Academy of Specialists in Tuberculosis, the American Academy of Chest Physicians and the National Tuberculosis Association. Dr. Rosencrantz was certified in Internal Medicine in 1937.

That year she became lecturer in Medical History and Bibliography, and retired as associate professor emeritus in 1943. In retirement Dr. Rosencrantz devoted her time to organizing and cataloging her collections of Osleriana, Garrisoniana, Fultoniana and others. She died December 17, 1950, of arteriosclerotic heart disease.