Born in London 1842

Alfred Marshall elevated economics from a branch of moral philosophy into an independent science, founding neoclassical economics. Principles of Economics (1890) synthesized classical theory with the marginal revolution, building a framework centered on supply-demand equilibrium.

Born in Bermondsey, London, to a Bank of England cashier and strict Evangelical father, Marshall defied family expectations to study mathematics at St John's College, Cambridge, placing Second Wrangler in 1865.

A mental crisis turned him toward metaphysics; Mill's writings then drew him to social justice. Walking London's slums proved decisive, leading him to seek solutions through economics. Appointed moral sciences lecturer in 1868, he later studied in Germany, absorbing Kant, Hegel, and Historical School methods.

In 1877 he married former student Mary Paley. Fellowship rules forced his resignation; he became principal at Bristol's University College. Their Economics of Industry (1879) replaced Mill's textbook. Returning as Cambridge professor of political economy in 1884, he won independence for economics as a discipline in 1903.

Principles appeared in 1890 and dominated teaching for half a century. It introduced the scissors metaphor, short-run versus long-run distinction, consumer surplus, price elasticity, and the representative firm. Marshall used math extensively but confined equations to footnotes, keeping text intuitive. Perfectionism left the second volume unfinished.

He died in 1924 aged eighty-one. Keynes called him the greatest economist of the preceding century.