In this interview, David Zierler, Oral Historian for AIP, interviews Lillian McDermott, professor emeritus of physics at the University of Washington. McDermott recounts her experiences growing up in New York City as a child of Greek immigrants. She discusses how her education at an all-female high school (Hunter) and all-female college (Vassar) supported her choice to major in physics and, subsequently, to pursue graduate studies at Columbia. McDermott describes how she created professional opportunities despite the barriers facing married women in academia and the demands of co-parenting three children. She started working at the University of Washington Physics Department as a volunteer and eventually rose to become the first woman to be appointed, and then tenured, as a professor. McDermott explains the circumstances leading to her pioneering work in physics education research and the co-evolution of the field and of the UW Physics Education Group (PEG). She describes how the Group’s collaborative, systematic research on learning and effective methods of teaching physics has shown the way towards transforming physics education — at elementary to university levels -- from manipulation of memorized formulas to a process of active inquiry.