John Williams was a prominent, prolific, and much-loved member of the Singapore philosophy community. He arrived in Singapore in the early 1980s from the University of Hull, where he obtained his Ph.D. under Alan R. White. He also had an M.Sc. in knowledge-based systems from the School of Cognitive Sciences at Sussex University. He was thereafter largely based in Singapore, where he taught logic and philosophy to countless generations of students, first as Lecturer at the Philosophy Department of the National University of Singapore and subsequently as Associate Professor at the School of Social Sciences, Singapore Management University. Interspersed with these appointments were brief stints in Jamaica, as Head of the Unit of Philosophy at the University of West Indies; South Africa, as Visiting Fellow at Rhodes University; and, most recently, the Republic of Kazakhstan, as Professor at the School of Humanities and Social Sciences, Nazarbayev University. John was an authority on, and lifelong student of, Moore’s paradox. His first publication was a 1979 Analysis paper, ‘Moore’s Paradox: One or Two?,’ and he published continuously and extensively in this area, exploring the paradox from many angles. With Mitchell Green, he co-edited the 2007 collection, Moore’s Paradox: New Essays on Belief, Rationality, and the First-Person (Oxford University Press). At the time of his death, he was working on a single-authored book, A Unified Treatment of Moore’s Paradox: Belief, Knowledge, Assertion, and Rationality, under contract with Oxford University Press. His interests ranged over the theory of knowledge, philosophy of religion, applied ethics, and logical paradox, and he published widely in these areas as well—a notable, recent instance being a discovery, with Neil Sinhababu, of a fascinating counterexample to Robert Nozick’s truth-tracking account of propositional knowledge, in the form of a backward-ticking clock. (‘The Backward Clock, Truth-Tracking, and Safety,’ Journal of Philosophy, vol. 112, 2015.) Both in person and in writing, John was ever-inventive, witty, and humorous. He loved beer, good conversation, karaoke, and bicycling in the hills of Sumatra. He passed away in August 2019 in Singapore after a short illness. A brilliant, funny, gregarious, and humble man, he will be dearly missed by his family, the Singapore philosophy community, and everyone else who knew him.