James Hartle is Professor of Physics at the University of California Santa Barbara where he has taught general relativity for over thirty years. His scientific work is concerned with the application of general relativity to realistic astrophysical situations, especially cosmology. He has contributed usefully the the understanding of gravitational waves, relativistic stars, and black holes. He is currently interested in the earliest moments of the big bang where the subjects of quantum mechanics, quantum gravity, and cosmology overlap. He is a member of the US National Academy of Sciences, a fellow of the American Academy of Arts and Sciences, and a past director of the Institute for Theoretical Physics in Santa Barbara.