After serving as a 2nd Lieutenant in the U.S. Army during the Korean War, Titley earned his doctorate in geology from the University of Arizona (UA). After two years as Regional Exploration Geologist for New Jersey Zinc Company, he joined the UA faculty in 1960 rising through the ranks to Distinguished Professor of Geosciences. His research in the search for the origin of porphyry copper deposits took him to more than 30 countries. It led him to investigate all scales of copper deposits, from entire deposits down to the level of atoms. Considered a world authority on Phanerozoic porphyry copper deposits, metal provinces, and metallogenesis, the books he wrote and edited along with the scholarly articles he published on porphyry copper deposits of southwestern North America are still widely read today. In 1964, Titley was selected by the U.S. Geological Survey to map the moon by telescope. Before humans landed on the moon, Titley trained NASA Apollo astronauts Alan Shepard, Scott Carpenter, Wally Schirra, Gordon Cooper, Ed White, and Thomas Stafford in the geology they would need to explore the moon. Widely recognized for his ground-breaking work in the fields of economic geology, engineering, and science, Titley's list of awards is lengthy. He was elected to the National Academy of Engineering, received the D.C. Jackling Award from the Society of Mining, Metallurgy and Exploration (SME), and from the Society of Economic Geologists (SEG) he was awarded the Penrose Gold Medal and honored as a Thayer Lindsley Distinguished Lecturer. For excellence in teaching, he received the Career Distinguished Teaching Award as well as the Creative Teaching Award from the University of Arizona, College of Science, among many other awards. Titley's 56 years of continuous teaching and research have left an enduring legacy of educating students so that they, too, have become leaders in their fields.