How do actors do what they do? How do they stir up emotions, both in themselves and in us as we watch them? Joseph Roach’s 1985 book The Player’s Passion: Studies in the Science of Acting examined how the actor’s art has been understood through history: from Shakespeare’s 17th century, when spirits emitted by actors’ eyes took hold of audiences, to David Garrick’s 18th century, when pneumatic tubes transmitted emotion from the brain to the body. We talk with Joseph Roach about historical theories of acting. These theories—shared by doctors, scientists, actors, and audiences—affected the way some of our favorite playwrights wrote, and some of them even made their way into the most influential acting techniques of the  20th century. Joseph Roach was the long-time Sterling Professor of Theater at Yale University. The Player’s Passion: Studies in the Science of Acting, one of a number of books by Roach, was originally published by the University of Delaware Press in 1985 and was reissued by the University of Michigan Press in 1993. He recently joined us at the Folger Institute for a seminar titled “What Acting Is.” He is interviewed by Barbara Bogaev. From the Shakespeare Unlimited podcast series. Published March 5, 2019. © Folger Shakespeare Library. All rights reserved. This podcast episode, “Suit the Action to the Word, the Word to the Action,” was produced by Richard Paul. Garland Scott is the associate producer. It was edited by Gail Kern Paster. Ben Lauer is the web producer. We had technical help from Andrew Feliciano and Evan Marquart at Voice Trax West in Studio City, California, and Ryan McEvoy at the Yale University Broadcast Center.