Mark William Coffey, 61, of Boulder, Colorado, died October 17, 2019. Mark was a lecturer in the Mathematical and Statistical Sciences department. He was teaching the Quantum Computing class this semester, and he taught Numerical Analysis in Summer 2019. He was born October 24, 1957 in Lincoln, Nebraska, the son of William D. and Patricia A. (Morgan) Coffey. He was raised in Nebraska and Iowa and received his undergraduate degree from the University of Iowa. He earned a Ph.D. in mathematics from the New York University Courant Institute of Mathematics and a Ph.D. in physics from Iowa State University. His research areas included theoretical physics and applied mathematics. He worked for IBM, the National Institute of Standards and Technology, the University of Colorado, and Colorado School of Mines. He was an amateur geologist who loved to hike, and he climbed many 14,000-foot mountains in the Colorado Rockies. He is preceded in death by his parents, and is survived by his brother Milo, of Ft. Dodge, Iowa, and his sister, Laurel Crusinberry, of Lincoln, Nebraska. In lieu of flowers, memorials may be made to the Children’s Tumor Foundation for research on neurofibromatosis.