Christa Sadler is a geologist, educator, wilderness guide, and writer with a serious addiction to rivers, deserts, and mountains. Her research in archeology, geology, and paleontology has included several ridiculously hot summers searching for dinosaurs in the badlands of Montana, fighting off dust storms and overly curious camels in the Gobi Desert in Mongolia, and steering clear of annoyed marine iguanas in the Galapagos Islands. In 2003, Christa participated in a National Geographic research grant to find and catalog fossil vertebrate in the Grand Canyon. She appeared in the July 1996 and June 2004 issues of National Geographic magazine in connection with her work in the Gobi Desert and the Grand Canyon. Christa is the author of Life in Stone, a book about the fossil history of the Colorado Plateau, and she has published an anthology of short stories by boatmen on the Colorado River. She has taught introductory geology and paleontology courses at Northern Arizona University and other Arizona colleges, works as an instructor for the Grand Canyon Field Institute, and runs geology programs for park service staff at Grand Canyon National Park.