John Clive Ward was a British-Australian physicist. His most famous creation was the Wardâ€“Takahashi identity, originally known as "Ward Identity". This celebrated result, in quantum electrodynamics, was inspired by a conjecture of Dyson and was disclosed in a one-half page letter typical of Ward's succinct style. In their recent book entitled Quantum Electrodynamics, Greiner and Reinhardt state in their discussion of charge renormalization: "Yet the Ward Identity has a much more fundamental significance: it ensures the universality of the electromagnetic interaction."
In his book The Infinity Puzzle, Frank Close devotes a whole chapter to this Ward creation and entitles it The Identity of John Ward, in which he writes: "Ward Identities lie at the very foundations of renormalization."
Andrei Sakharov classified Ward as one of the "titans" of quantum electrodynamics alongside Dyson, Feynman, Schwinger, and Tomonaga. In this regard, it has been said that physicists have made use of his principles and developments "often without knowing it, and generally without quoting him."