Alfred Marshall (26 July 1842 – 13 July 1924) was an English economist, and was one of the most influential economists of his time. His book Principles of Economics (1890) was the dominant economic textbook in England for many years. It brought the ideas of supply and demand, marginal utility, and costs of production into a coherent whole. He is known as one of the founders of neoclassical economics. Life and career Marshall was born at Bermondsey in London, second son of William Marshall (1812–1901), clerk and cashier at the Bank of England, and Rebecca (1817–1878), daughter of butcher Thomas Oliver, from whom, on her mother's death, she inherited property. William Marshall was a devout strict Evangelical, "author of an Evangelical epic in a sort of Anglo-Saxon language of his own invention which found some favour in its appropriate circles" and of a tract titled Men's Rights and Women's Duties. Marshall had two brothers and two sisters; a cousin was the economist Ralph Hawtrey. The Marshalls were a West Country clerical family; Marshall's great-great-grandfather was "the Reverend William Marshall, half-legendary Herculean parson of Devonshire", famous for "twisting horseshoes with his hands" to scare "local blacksmiths into fearing that they blew their bellows for the devil". Marshall grew up in Clapham and was educated at the Merchant Taylors' School and St John's College, Cambridge, where he demonstrated an aptitude in mathematics, achieving the rank of Second Wrangler in the 1865 Cambridge Mathematical Tripos. Marshall experienced a mental crisis that led him to abandon physics and switch to philosophy. He began with metaphysics, specifically "the philosophical foundation of knowledge, especially in relation to theology". Metaphysics led Marshall to ethics, specifically a Sidgwickian version of utilitarianism; ethics, in turn, led him to economics, because economics played an essential role in providing the preconditions for the improvement of the working class. He saw that the duty of economics was to improve material conditions, but such improvement would occur, Marshall believed, only in connection with social and political forces. His interest in Georgism, liberalism, socialism, trade unions, women's education, poverty and progress reflect the influence of his early social philosophy on his later activities and writings. Marshall was elected in 1865 to a fellowship at St John's College at Cambridge, and became lecturer in the moral sciences in 1868. He was Mary Paley's professor of political economy at Cambridge and the two were married in