Donald K. Mason, of Sun City Center, Florida, passed away suddenly on July 19, 2025. He was born in Terre Haute, Indiana, on September 27, 1935, and grew up in Griffith, Indiana.

Don began his studies at Purdue University, attending for two years before enlisting in the U.S. Army, where he served as a military policeman stationed in Okinawa. After completing his service, he returned to Purdue and earned his degree in statistics in 1959.

On June 30, 1962, he married Marlene D. Lahaie in Marinette, Wisconsin. The couple moved to San Jose, California, where Don worked as a statistician at Lockheed Missiles & Space. While in San Jose, he earned his master’s degree in mathematics from San Jose State University in 1967. Their daughter, Michelle L. Mason, was born in San Jose in 1964.

In pursuit of further education, the family moved to Evanston, Illinois, where Don earned his Ph.D. in mathematics from Northwestern University in 1972. Their son, Scott K. Mason, was born in Evanston in 1967.

Don began his career as a mathematics professor at Elmhurst University in Elmhurst, Illinois, in 1973. He devoted nearly three decades to his passion for teaching before retiring in 2001, when he was honored with the title of Professor Emeritus. He was also the author of the Student Solutions Manual for Elementary Statistics, a valuable resource for students of the subject.

In retirement, Don enjoyed life in Sun City Center, where he was an enthusiastic member of the Beer and Wine Tasting Club. But above all, Don cherished his family. He was a devoted husband, father, and grandfather, and he took great pride in the accomplishments of his loved ones.

Don is survived by his wife of 63 years, Marlene; daughter Michelle, of Sun City Center; son Scott, of Fraser, Colorado; and granddaughter Hannah E. Mason, of Flagstaff, Arizona. He is also survived by his nieces and their families.

A celebration of life for Don will be held on September 27, 2025, which would have been his 90th birthday, in Kings Point Banquet Room, from 1pm to 4pm.