Martin Lockley is the associate professor of geology at the University of Colorado, Denver, and author of more than two hundred books, most recently, Tracking Dinosaurs: A New Look at the Ancient World and Dinosaur Tracks and Traces, which he co-authored with David Gillette. Adrian P. Hunt is a former co-curator of the University of Colorado, Denver, Dinosaur Tracks Collection and is director of the Mesalands Dinosaur Museum, Mesa College, Tucumari, New Mexico. He is the author of more than two hundred papers and other publications on various topics in paleontology and has coedited the book Dawn of the Age of Dinosaurs in the American Southwest.