This interview surveys Baum's career as a physicist at the Naval Research Laboratory (NRL) and astronomer at Mt. Wilson and Palomar Observatories. After sketching Baum's early life, the discussion concentrates on Baum's role in the development of spectroscopy research at NRL, specifically his work on the UV spectrum of the sun - including the first successful UV spectra of the sun. Aspects of his experience in experimentation with V-2s and Aerobees, and his thesis research on rockets at CALTECH (PhD, 1950, physics) are also explored. Additional topics discussed include: Optics Division, NRL; White Sands Proving Ground (NM); relationships with, and costs and descriptions of Baird Atomic; V-2 missile experiments, development and launch; meetings with Werner Von Braun; and contacts with R.W. Wood, J. Strong, Lyman, Stockbarger, and Tousey.