William E. Glassley (July 1, 1947 – March 19, 2023) was a geologist at the University of California, Davis and a researcher at Aarhus University, Denmark, focusing on the evolution of continents and the processes that energize them. He was the author of over seventy research articles and a textbook on geothermal energy. A Wilder Time: Notes from a Geologist at the Edge of the Greenland Ice, his first book for a general audience, received the John Burroughs Medal for Distinguished Natural History Book and the New Mexico-Arizona Book Award, among other honors.