Marshall, Alfred, 1842-1924, English economist. At Cambridge, where he taught from 1885 to 1908, he exerted great influence on the development of economic thought of the time; one of his students was John Maynard Keynes. He systematized the classical economic theories and made new analyses in the same manner, thus laying the foundation of the neoclassical school of economics. He was concerned with theories of costs, value, and distribution and developed a concept of marginal utility. His Principles of Economics (1890) was for years the standard work and is still widely read. Among his other works are Industry and Trade (1919) and Money, Credit, and Commerce (1923).