Robert Levenson of UC Berkeley discusses his decades of research on the physiology of emotion, part of Yale's Experts in Emotion interview series produced by June Gruber. He traces how he became interested in emotion research, then walks through central findings from his lab, including work linking autonomic nervous system patterns to specific emotional states and studies of emotional behavior in long-term marriages. Levenson describes methods for measuring heart rate, skin conductance, and other physiological signals alongside observed behavior to understand how emotions unfold in the body. He addresses where he thinks the field is headed, including questions about emotion regulation and aging, and closes with practical advice for students considering a career studying emotion. The format is a straightforward chaptered interview, with timestamps marking his origin story, his key discoveries, his forecast for the field, and his closing advice.