Gregory Zilboorg was a psychoanalyst and historian of psychiatry. His many writings and lectures situated psychiatry within a broad sociological and humanistic context at a time when psychoanalysis was gaining importance in literary culture.

Zilboorg was born in Kiev on December 25, 1890 and studied medicine in Petrograd (St. Petersburg). In 1917 he served in the Ministry of Labor for two presidents (Aleksandr Kerenskii and Georgii L'vov). In 1919 he emigrated to the United States and for a time translated plays from Russian to English while studying medicine at Columbia University. After graduating in 1926, he worked at the Bloomingdale Hospital and eventually established a psychoanalitic practice in New York City. From the 1930s onward, Zilboorg produced several volumes of lasting importance on the history of psychiatry. The Medical Man and the Witch During the Renaissance began as the Noguchi lectures at Johns Hopkins University in 1935. This volume was followed by History of Medical Psychology in 1941 and Sigmund Freud in 1951.

Zilboorg's analytic practice brought him into contact with prominent figures in New York's literary and theater milieu. His patients included Marshall Field, George Gershwin, Lillian Hellman, Ralph Ingersoll, Kay Swift and James Warburg. Another of his patients, Moss Hart, drew on his experience in psychoanalysis when writing the musical Lady in the Dark.

Zilboorg was also an avid photographer. His portraits of John Farquhar Fulton and Henry Sigerist were featured in obituaries published in the Journal of the History of Medicine and Allied Sciences, Inc.

Zilboorg married Ray Liebow in 1919 and they had two children (Nancy and Gregory, Jr.). He married Margaret Stone in 1946 and they had three children (Caroline, John and Matthew).