Westin Harbor Castle Hotel, Toronto, Ontario, Canada
This interview is part of a small program to document the recent history of the American Astronomical Society (AAS). These interviews were used as background studies to help authors of chapters of the centennial history volume of the Society research and organize documentary materials. The volume to be published in 1999. This interview discusses Baum's attendence at the AAS meetings in the early 1950s; Ira Bowen, director of Mt. Wilson-Palomar Observatories; Baum's role in developing photoelectric system for use at Palomar and using the system to study stars of globular clusters.