Donald "Don" Calvin Mesner passed away on April 27, 2023, at the age of 91. He died peacefully after entering hospice care for a short period of time. He will be deeply missed by his loving family. Don was born in Klamath Falls, Oregon, May 13, 1931, to Violet Emma (Biwer) and Harry Calvin Mesner. Don was raised in Big Lakes Box Company logging camps until fifth grade when his family moved to Klamath Falls. Don graduated from Klamath Union High in 1949 and went on to attend Oregon State University where graduated in 1954 with a degree in Industrial Engineering. He married his college sweetheart, Marilyn "Lyn" Perkins, also of Klamath Falls, during his last term of college and entered Army Artillery at Fort Sill, Oklahoma. They welcomed their daughter, Gayle, before Don left the military as a 1st Lieutenant in March 1956, and eventually relocated to Canoga Park, California, where they soon welcomed their son, Dean. Don enjoyed a long and varied career as an engineer. Areas of employment included aeropropulsion (Marquart Company), design and fabrication (self-owned heavy materials handling equipment company) and, later, designing and fabricating equipment for deep water exploration. Upon retirement in 1996, Don and Lyn moved to Valley Center, California, where they enjoyed traveling, tending to their lemon grove and spending time with their growing family. They were active in the Valley Center community and participated in fun local events including parades, pancake breakfasts and other fundraisers. Don also loved playing bridge, was an avid reader and enjoyed listening to instrumental music. Don was preceded in death by his wife, Lyn, and his brother, William "Bill," of Klamath Falls. In addition to Gayle and Dean and their spouses Mike Marinkovich and Lynda Mesner, Don is survived by his sister, Marian Hamilton of Yreka, California, and Cindy Narramore, of Mountain Home, Idaho; his four grandsons, Matt (Suzy) Marinkovich, Luke (Alexis) Marinkovich, Jake Mesner and Shane Mesner; his five great-grandchildren, Calvin, Rue, Reed, Joan and Leo. Don was also preceded in death by his companion, Marjorie Narramore, of Klamath Falls. Don lived a long, unique and fulfilled life. At his request, no public services will be held; please honor him in your heart.