(February 7, 2011) Leonard Susskind gives a lecture on string theory and particle physics that focuses again on black holes and how light behaves around a black hole. He uses his own theories to mathematically explain the behavior of a black hole and the area around it. In the last of course of this series, Leonard Susskind continues his exploration of string theory that attempts to reconcile quantum mechanics and general relativity. In particular, the course focuses on string theory with regard to important issues in contemporary physics.