Dr William John Kossler (Jack) passed away in his early morning sleep on December 9, 2021, leaving behind three sons, two grandchildren, a new great-grandchild and many good friends who admired him . Jack was a scientist, teacher, handyman, father, sailor, swimmer, tennis player, and good friend to many. He taught physics at the College of William and Mary for 43 years. He was calm, caring and kind. He was a father of three, a grandfather of two and most recently a great grandfather. Jack was born March 26, 1937 in Charleston, South Carolina, to William John and Lois Gordon Kossler. He received a bachelor’s degree from the Massachusetts Institute of Technology in 1959, then received his doctorate in physics from Princeton University in 1964. After being an assistant professor at MIT for three years, he moved to Williamsburg, where he taught. physics at the College of William. and Mary from 1969 to 2012. As an experimental physicist, he traveled the world working and testing hypotheses in different particle accelerators. In 1977, the whole family moved to Switzerland for a year while he was working at the Swiss Institute for Nuclear Research (Schweizerisches Institut fuer Nuklearforschung), enrolling his sons in local public schools. The experience instilled in his sons a love of travel and an appreciation of other cultures. He had loved sailing since learning to sail as a teenager, living in Belle Haven, Alexandria and attending Fishburne Military Academy. Jack has taken his family to Mobjack Bay on numerous summer weekends over the past half century, on a series of small sailboats of varying degrees of repair. He was proud of his father, who helped adapt the emerging helicopter for Coast Guard rescue work and to this day, the Coast Guard gives Captain William J. Kossler every year for the greatest achievement in the practical application or operation of a vertical flight aircraft. . In retirement, he remained involved in the physics department of the university, volunteered to help with the National Science Foundation’s undergraduate research experience program, and served on the thesis committees of the National Science Foundation. doctoral students. He volunteered his time tutoring high school students in Venice, Florida and Virginia. In his spare time he would swim, play tennis, and always DIY several projects at once. He had custom lenses and used them to build a functionally identical telescope to the one Galileo first built. This played a role in a recent OSHER conference on the role of accidental discoveries in the history of science. Most recently he was working on a computer program designed to transform a large volume of historical data in legacy formats into a form usable with current technology. Jack’s distinguished career was unusual, in that he straddled two subfields of physics: one concerned the particles that make up the universe and the other the properties of solid matter. Most of the world around us is made up of three particles: the proton, the neutron, and the electron. In 1936, physicists were surprised by the discovery of a new member of the particle family: the muon, denoted by the Greek letter? (pronounced mu, as in the word music). At the time, the witty Nobel Prize winner Isidor Rabi exclaimed, “Who ordered this? Jack’s work, for which he was awarded the honorary title of “Fellow of the American Physical Society”, has been devoted to answering this question. Unlike its three rather indestructible cousins, the muon only lives a few microseconds before spontaneously disintegrating into fragments. If you want to study it, you have to be nimble. Particle physicists are continuing this work in a handful of large particle accelerators capable of producing muons. It took thirty years before practical use was found for muons in a different and older branch of physics – the study of solids, such as metals and crystals. Since particle physicists differ from solid physicists about as much as plumbers differ from electricians, it is a testament to Jack’s remarkable creativity and versatility that he became one of the pioneers of a hybrid branch of physics called Muon Spin Rotation (? SR). In this technique, muons are injected inside a solid where their movement is affected by internal magnetic fields. Their decay fragments escape from the solid and are detected, taking with them important clues to these inaccessible fields. Mapping these fields inside solids has greatly contributed to our understanding of superconductors. In search of suitable sources of muons, Jack had to travel to remote places such as Brookhaven NY, Vancouver, British Columbia, and Brugg, Switzerland. Today, SR is a thriving niche in physics, with its own journals, conferences, and textbooks. The community? SR will mourn and remember Jack as one of its pioneers. He has been listed as an Outstanding Physics Educator by Marquis Who’s Who, and has 161 articles, journal articles, and other publications to his name. He is predeceased by his wife, Margaret O’Neil Kossler in 2018. He is survived by his three sons: Neil, of Fairfax County VA, Bill and Paul of Richmond VA, wife of Bill Shari, grandchildren Spenser Kossler and Brittney Smoot of Loudoun County and great granddaughter Margaret. Lois Manes, a dear friend of the family for many years, was particularly close to Jack in recent years. His spirit and his love of seeking knowledge live on in the memory of all who knew him. A memorial service will be held on Saturday, January 15 at 1 p.m. at the Williamsburg United Methodist Church, 500 Jamestown Rd, Williamsburg, VA 23185. Condolences can be made online at www.bucktroutfuneralhome.net.