Professor Frank Ambrose McClintock died at 90 on February 20, 2011. He was born on January 2, 1921 in St. Paul, Minnesota, son of Professor Henry Lacy McClintock and Charlotte Smith. He earned S.B. ('42) and S.M. ('43) degrees in Mechanical Engineering from MIT. During WWII, he worked for three years at Pratt and Whitney, one of eight engineers who were developing the jet engine. He then moved to the California Institute of Technology, earning his Ph.D. in 1949. McClintock then returned to MIT as an Assistant Professor in the Department of Mechanical Engineering, teaching and leading many research programs focused on understanding why things break. He retired as Professor Emeritus, at age 70, but continued research and publishing until 2006 when he was 85. Professor McClintock was a pioneer in melding applied mechanics with materials science in the teaching of Mechanical Behavior of Materials to undergraduates. In 1966, he and his co-author Professor Ali Argon published a book with the same title, which is still in print today. His professional contributions revolutionized the understanding of the fracture process, applying it through engineering practice to reduce injuries, protect the environment and save lives; he reduced breakage of the blades in gas turbine and jet engines, helicopter rotors, and aging radioactive waste tanks. His trend setting publications, which continued strong until very recent times, were recognized by a series of prestigious awards, starting with the James Clayton Prize of Britain in 1956. The Nadai Award and the Drucker Medal of the ASME, the Howe Medal of the ASM, and the Griffith Medal of the ESIS followed. The University of Glasgow, Scotland, gave him an honorary Doctorate of Laws. McClintock was elected both a Fellow of the American Academy of Arts and Sciences and a Member of the National Academy of Engineering. Throughout his life, Frank passionately enjoyed skiing, competing as a young man in downhill, cross-country and ski-jumping, continuing into his late 80's. He was equally devoted to hiking and rock-climbing in the East and throughout the West. As a boy he learned technical rock climbing with his father, an elected member of the American Alpine Club, particularly in the San Juan and Needle Mountains of southwestern Colorado as well as the Tetons in Wyoming, where McClintock Peak was named to honor the first ascent made by Frank and his father. He shared his love of Colorado rock climbing and route finding with his children on many summer camping trips, centered around the mining town of Ouray, Colorado, nestled deep in the mountains. A former Eagle Scout, he served as a Boy Scout leader in Concord. He was active in the First Parish Meetinghouse as a member of the Humanist Group and served in diverse ways including usher, church schoolteacher, member of the standing committee, and Deacon. He is survived by Mary of Concord, his wife of 66 years, and their four children: Martha and her husband Joel Charrow of Chicago, Illinois and their children Ben and Julia; Roger and his wife Jane Jeffries, presently on the high seas off Thailand; David and his wife Nancy of Lyman, Maine and their daughter Sue; and Richard and his daughters Charlotte and Rayna of Denver, Colorado. His memorial service was held on Saturday February 26, 2011 at the First Parish in Concord. Any memorial gifts may be sent in Frank A. McClintock's name to the Ouray Trail Group P.O. Box 50, Ouray, CO 81427. Frank's beloved mountains can be enjoyed at http://www.ouraytrails.org. Arrangements are under the care of Charles W. Dee and Susan M. Dee, Dee Funeral Home of Concord. Memorials: Please send any donations in Frank McClintock's name to the Ouray Trail Group, P.O. Box 50, Ouray, CO 81427 (http://www.ouraytrails.org). Service: The service will be held Saturday, February 26, 2011 at 2 PM at the First Parish Meetinghouse in Concord Massachusetts, followed by a reception in the parish hall.