W. S. Jevons, 1835–82

It is arguable that William Stanley Jevons has a better claim to the title ‘pioneer of modern economics’ than any of his British contemporaries. Forty-two years ago Keynes described Jevons’s Theory of Political Economy as ‘the first treatise to present in a finished form the theory of value based on subjective valuations, the marginal principle and the now familiar technique of the algebra and diagrams of the subject’.1 The Theory of Political Economy undoubtedly succeeded in doing what Jevons, equally undoubtedly, intended it to do — to mark a sharp break with all previous presentations of the principles of the subject. As a result it gained him a sharply-defined place in the history of economic thought as one of the initiators of what has come to be called the Marginal Revolution. Yet at the same time this very success has tended to overshadow the rest of Jevons’s economic writing and to some extent prevented a balanced assessment of his achievements as an economist from becoming generally known.