Dr. Joel Hass received his PhD from the University of California Berkeley. He is currently a professor of mathematics at the University of California Davis. Joel has coauthored widely used calculus texts as well as calculus study guides. He is currently on the editorial board of several publications, including the Notices of the American Mathematical Society. Dr. Hass has been a member of the Institute for Advanced Study at Princeton University and of the Mathematical Sciences Research Institute, and he was a Sloan Research Fellow. Joel’s current areas of research include the geometry of proteins, applied mathematics, three dimensional manifolds,and computational complexity. In his free time, Joel enjoys kayaking.