Ronald Franklin Holsinger, of Carlisle, MA, passed on June 25, 2021 at the age of 87 from a long battle with dementia. Ron - also known as "Big Ron", "Pop", "Da" and "Daddy" - was born in Idaho in 1934. He spent his childhood in Texas and Utah. He was always a bit of a wild man and after a year of college in Texas, he set out to California on his motorcycle after receiving a scholarship to study at Stanford. After studying at Stanford, he joined Klaus Halbach - unbeknownst to him at time, his future father in law - at the Lawrence Berkeley National Lab at UC Berkeley with his work on magnetic systems for particle accelerators. Together, they developed code that is still used today in analyzing and designing conventional magnets. Those codes are used in everything from vaccine research and Tesla electric motors. After marrying Klaus's daughter, Terry, in 1965, the family moved to Switzerland where Ron has received a research position at the prestigious CERN labs (he had lost the motorcycle at that point). Another move brought the family to Santa Fe, New Mexico where he worked at the Los Alamos National Lab. Eventually, the family made its way to Carlisle where Ron took a job at New England Nuclear and eventually, he started his own company, Field Effects which he sold and then started yet another company, Aster Enterprises. He was an exceptional mind - always fixing things and tinkering away. He had every tool imaginable - every saw and drill one could need - and he had a few run-ins with those tools that left him with scars and stories to tell! He loved his Apple computers - he was an early adopter of Apple technology and at one point, insisted that all of his children use Macs - no excuses. He was happiest on his Kubota tractor pushing dirt around in the garden in Carlisle or plowing the driveway in the winter. Key West was his happy place - he took his family for years down to the island for rest and relaxation. He got a kick out of Duval Street and would always rent a Jeep and loved to watch the sunset from the pier. If you ever had an entrepreneurial idea he was ready to listen - if you had some dark chocolate and red wine. Ron also loved his dogs over the years: Emma, Daisy, Blake, Bella - he walked them all the time and if you ever had dinner at his house, you had to watch your plate, because as soon as you were done, Ron would whisk it off the table and make sure the dog was able to lick it clean! Ron is survived by his wife Terry Holsinger of Carlisle, MA as well as five children: Heather Holsinger, Garth Holsinger of Nevada, Suzy Holsinger her husband Tom Branca of Oakland, CA, Chris and Amy Holsinger of Pepperell, MA, and Ronnie and Megan Holsinger of Concord, MA. He is predeceased by his first child, Vicki. He is also survived by 6 grandchildren - Rebecca Branca and Lily Rose and Roman Branca-Holsinger, Lizzy Holsinger, and Grace and Teddy Holsinger. In addition to his children and grandchildren, he is survived by his sister Cherene Unrau and her husband Norm and their daughter Amy, as well as his brother Dick Holsinger. Lastly, he is survived by his beloved mother in law - Ruth Halbach. All are welcome to attend visiting hours on Wednesday, June 30th from 4 to 6 pm at Dee Funeral Home, 27 Bedford Street, Concord, MA. In lieu of flowers, Ron would have loved it if you made a donation to the MSPCA . Arrangements are under the care of Dee Funeral Home & Cremation Service of Concord.