AIP Oral Historian David Zierler interviews Dr. Mary Gaillard, Professor of the Graduate School, University of California, Berkeley and Affiliate Senior Scientist at Lawrence Berkeley Laboratory. Dr. Gaillard discusses her experiences as an undergraduate at Hollins College in Virginia, and as a graduate student first at Columbia University, then at the University of Paris at Orsay. She describes her subsequent research on kaons and baryon decay while working for the French National Center for Scientific Research at CERN, her year-long collaboration with Ben Lee at Fermilab, and her eventual return to the United States as the first woman to be a tenured professor in the Department of Physics at UC Berkeley, focusing in particular on the working environment at each institution. The remainder of the interview deals with the state of theoretical physics over the course of her career and through to the present.