David Thomson didn't necessarily convince me that acting "matters" per se, but it was thoroughly enjoyable reading his argument. Essentially he believes that humans are actors( hence the gorilla on the front cover). The ubiquity of television and movies since the 20th century has seeped into our conscious and unconscious minds, shaping and changing forever the way we present ourselves to the world. Thomson reaches back to Shakespeare and connects theatre to movies through the Barrymores. His interest, however, is really film, and no one can beat his knowledge of film technique and how it shapes what actors do. Well worth a read if you're curious about the purpose and significance of acting.