Saul Perlmutter, Ph.D., is an astrophysicist and cosmologist who received the Nobel Prize in Physics for discovering that the expansion of our universe is accelerating. He leads one of NASA’s science teams for the Nancy Grace Roman Space Telescope, and also develops and teaches courses on scientific-style critical thinking for scientists and nonscientists alike. Further honors for his groundbreaking research include the Shaw Prize in Astronomy, the Breakthrough Prize in Fundamental Physics, and the Albert Einstein Medal. He is the Franklin W. and Karen Weber Dabby Professor of Physics and Director of the Berkeley Institute for Data Science at University of California, Berkeley and Senior Scientist at Lawrence Berkeley National Laboratory.