For the last four years, Jon and I were colleagues. It’s hard for me to put into words a single impression of Jon. He was a force of nature, uncontainable and omnipresent. His passion for knowledge was insatiable and drove him to a breadth of research that is extremely rare in modern times. He was a generous host and doting grandfather—a talk with Jon inevitably started with a slew of stories of what happened with his grandkids over the weekend. He was a strategic leader, going into centres and societies and universities and academies with intention and agency. I saw him build our Centre (CARMA), guide students and postdocs, and mentor young academics. He was polarising—you couldn’t work with Jon and not be moved to some kind of action. And in each of his projects, he drew people in and created opportunities for others. Those of us in Newcastle have benefited tremendously from Jon’s time with us. He took a fledgling group and built one of the strongest in Australia. We are forever changed, and in his debt. [Michael Coons, University of Newcastle (CARMA), Australia]