Stephen Marshak is professor of geology at the University of Illinois, Urbana-Champaign, where he is also the director of the School of Earth, Society, and Environment. He holds an A.B. from Cornell University, an M.S. from the University of Arizona, and a Ph.D. from Columbia University. Steve's research interests lie in structural geology and tectonics. This work has taken him into the field on a number of continents. Steve loves teaching and has won his college's and university's highest teaching awards. In addition to research papers and Earth Science, Steve has also authored Earth: Portrait of a Planet, Essentials of Geology, and has co-authored the Laboratory Manual for Introductory Geology, Earth Structure: An Introduction to Structural Geology and Tectonics, and Basic Methods of Structural Geology