Leonard Susskind gives the first lecture of a three-quarter sequence of courses that will explore the new revolutions in particle physics. In this lecture he explores light, particles and quantum field theory.Leonard Susskind, Felix Bloch Professor of Physics, received a PhD from Cornell University and has taught at Stanford since 1979. He has won both the Pregel Award from the New York Academy of Science and the J.J. Sakurai Prize in theoretical particle physics. He is also a member of the National Academy of Sciences.