Stephen Barr is a theoretical particle physicist. He received his Ph.D. from Princeton University in 1978 and has held research positions at the University of Pennsylvania, the University of Washington, and Brookhaven National Laboratory. He is currently a professor in the Department of Physics and Astronomy at the University of Delaware and director of its Bartol Research Institute. His physics research centers mainly on “grand unified theories”, the origin of quark and lepton masses, the theory of CP violation, and the cosmology of the early universe. He has written over 160 research papers and was elected a Fellow of the American Physical Society “for original contributions to grand unification, CP violation, and baryogenesis.” He writes and lectures extensively on the relation of science and religion, and his articles and book reviews on that subject have appeared in many widely-known publications, including First Things, on whose editorial advisory board he serves, The Public Interest, The Weekly Standard, National Review, Modern Age, and Commonweal. He is the author of Modern Physics and Ancient Faith (Notre Dame 2003), A Student’s Guide to Natural Science (Intercollegiate Studies Institute 2006), and The Believing Scientist: Essays on science and religion (Eerdmans 2016).