During the 1920s, Frank Ramsey made massive contributions to no fewer than four disciplines: philosophy, economics, mathematics and subjective utility theory. In 1999, the philosopher Donald Davidson caught his brilliance by coining the term the “Ramsey Effect”: when you discover that your exciting and apparently original philosophical discovery has already been presented, and presented more elegantly, by Frank Ramsey.

The 1920s were to be Ramsey’s only window in which to make his contributions. When the decade began, he was a seventeen year old, starting his mathematics undergraduate degree at Trinity College, Cambridge. Before he graduated, he had demolished John Maynard Keynes’s new theory of objective probability relations; made a valiant attempt at repairing a defect in Russell and Whitehead’s *Principia Mathematica*; translated Wittgenstein’s enormously difficult *Tractatus Logico-Philosophicus* from German to English; and published a critical notice of the *Tractatus* for the journal *Mind*, which still stands as one of the most challenging commentaries of that influential book.

This was a stunning run for an undergraduate. Keynes was building an economics empire at King’s and he knew a good thing when he saw it. In an impressive show of administrative skill and sleight of hand, he snapped up the young prodigy before Trinity could blink. Ramsey became a mathematics Lecturer and fellow of King’s College in the autumn of 1924. The next half of the decade would be even more productive than the first.

Ramsey didn’t let Keynes down. He wrote two papers in economics for Keynes’s *Economic Journal*. Each was so important that when the* Journal* celebrated its 125th anniversary with a special edition in 2015 of its thirteen greatest hits, the editors decided that both Ramsey’s papers needed to be included. “A Contribution to the Theory of Taxation” founded the sub-field of optimal taxation and laid the foundation for the field of macro-public finance, so much so that any research problem about optimal monetary or fiscal government policy is now called a Ramsey Problem. “A Mathematical Theory of Saving” tried to determine how much a nation should save for future generations and founded the field of optimal savings and development.