John C.H. Spence, Regents Professor of Physics at Arizona State University in Tempe, Arizona, and lately of Massachusetts, died on June 28th surrounded by his loving family. John's boundless curiosity about how things work led to an outstanding career in science. John was a music lover and keen musician, playing the piano, flute, and guitar, often with his rock band, Moon Dogs, and bossa nova band, Who Knew. He was also a sailor, pilot, and writer. He had recently published his third book, Spitfire Pilot, which documents the life of his fighter-pilot father Lou Spence, and in 2019 authored Lightspeed, the history of attempts to measure the speed of light. The textbook he wrote early in his career, Experimental High-Resolution Electron Microscopy has become a classic; required reading for every microscopist, and now in its 4th edition. John taught at Arizona State University for more than 40 years. He completed his PhD in physics at Melbourne University, followed by postdoctoral work at Oxford University. His research was in the fields of condensed matter physics, atomic-resolution electron microscopy and biophysics. He was the Director of Research for the NSF Science and Technology Center "BioxFEL", which has developed and applied the recently invented free-election X-ray laser to structural biology. This allows movies to be made of molecular machines at work, in order to understand atomic processes such as drug action and photosynthesis. John was a Foreign Member of The Royal Society, (an extremely rare distinction) and of the Australian Academy of Science. He was awarded the Gregori Aminoff Prize in 2021 for his contribution to the field of crystallography. John was born in Canberra, Australia. Following his father's death in the Korean War, John was raised in Melbourne by his mother, Vernon, together with his beloved sister Penny. With his wife, Margaret, he had many happy years and enjoyed traveling the world and spending time with friends. John passed on his love of science, vintage cars, and flying to his son Andrew Spence. He is also survived by his daughter-in-law Rebecka Rosenquist, grandchildren, Maja and Louis Spence, step-sons James, Daniel, and Peter Stanzler and their families, as well as family in the United Kingdom and Australia. A private family service will be held. Arrangements are under the care of Dee Funeral Home & Cremation Service of Concord.