Allan Ludman is a Professor in the Department of Earth and Environmental Sciences at Queens College, part of the City University of New York. He has devoted more than four decades to deciphering the evolution of the Northern Appalachians through field and laboratory studies in Maine and New Brunswick. He has taught introductory geology for 40 years and supervised the laboratories at Queens College for the past 35 years. Professor Ludman is also the director of GLOBE NY Metro, a K-12 science teacher development program in the New York area, created to promote hands-on, inquiry-based Earth Systems research for elementary and high-school level teachers and students.
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 AB from Cornell University, an MS from the University of Arizona, and a PhD from Columbia University. Steve's research interests lie in structural geology and tectonics. This work has taken him into the field on multiple continents. He has also won his college's and university's highest teaching awards. In addition to research papers and Earth: Portrait of a Planet, Steve has authored Essentials of Geology; and has co-authored Laboratory Manual for Introductory Geology; Earth Structure: An Introduction to Structural Geology and Tectonics; and Basic Methods of Structural Geology.