Donald Lyman Burkholder, a renowned mathematician who helped to revolutionize interdisciplinary studies in the areas of probability theory and analysis and who spent his entire career as a professor at the University of Illinois, died in his sleep on Sunday, April 14, 2013, in Urbana, Illinois. He was 86. He was born January 19, 1927, in Octavia, Nebraska, the fourth of five children of Elmer and Susan (Rothrock) Burkholder. In 1945, Don graduated from high school, where he was captain of the basketball team and senior class president, an honor (as he loved to relate) that came his way because his three classmates had all been president already. He was drafted and entered the Civilian Public Service as a conscientious objector, serving as a cook at a camp for fighting forest fires in Oregon and as an orderly at a mental hospital in New Jersey. Following his discharge in December, 1946, he acted on the recommendation of a friend and enrolled at Earlham College, a predominantly Quaker college in Richmond, Indiana. There he met his wife-to-be, Jean Annette Fox. After their wedding in June 1950, Don and Jean attended the University of Wisconsin in Madison as graduate students in sociology. In 1953 they went to the University of North Carolina at Chapel Hill, where Don had a fellowship to study sociological statistics. He soon discovered that his real interest lay in mathematics, and he completed a Ph.D. in statistics in 1955 under the guidance of Prof. Wassily Hoeffding. That summer, Don joined the Mathematics Department at the University of Illinois in Urbana, where he became a professor in 1964. In 1978 he was appointed Professor in the University of Illinois’ Center for Advanced Study. Don retired as professor emeritus in 1998. Don is survived by his wife of almost 63 years, Jean Annette (Fox) Burkholder; his son J. Peter Burkholder and son-in-law P. Douglas McKinney of Bloomington, Indiana; his son William F. Burkholder, daughter-in-law Joanne (McLean) Burkholder, and granddaughter Sylvie Kathleen Burkholder of Singapore; his sister Helen Dale and brother-in-law Ernie Dale of Auburn, Washington; his brother John Burkholder and sister-in-law Donna Burkholder of McPherson, Kansas; his sisters-in-law Anne Burkholder of McPherson, Kansas, and Leona Burkholder of Madison, Wisconsin; and seventeen nieces and nephews. His daughter Kathleen Linda Burkholder died of a cerebral hemorrhage in 1981, and he was predeceased by his brothers Robert Burkholder of Buhler, Kansas, and Wendell Burkholder of Madison, Wisconsin.