In 1954 Lewis published a paper on ‘Economic Development with Unlimited Supplies of Labour’, which spawned a whole literature on ‘dual economies’ - small, urban, industrialized sectors of economic activity surrounded by a large, rural, traditional sector, like minute islands set in a vast ocean - and put its stamp on the character of development economics for decades to come.

Lewis was born in St Lucia, West Indies. After attending high school in St Lucia, he entered the London School of Economics (LSE) in 1934, graduating in 1937. In 1938 he began teaching at the LSE where he remained until 1948, except for wartime service with the British Government at the Board of Trade and the Colonial Office. He received his MA from the University of Manchester and his doctorate from the University of London, both in the early 1940s. In 1948 he became a professor of economics at the University of Manchester where he spent an extremely productive decade. He left Manchester in 1958 to become principal of University College of the West Indies. When it was enlarged into the University of the West Indies in 1962, he became its first vice-chancellor. In 1963 Lewis was knighted by the British government and moved to the USA to take up a professorship at Princeton University. He left the USA in 1970 to take up the presidency of the Caribbean Development Bank but returned to Princeton in 1973. He was president of the American Economic Association in 1982.

His works include Development Planning: The Essentials of Economic Planning (1966), The Evolution of the International Economic Order (1977), Growth and Fluctuation, 1870-1913 (1978), and Selected Economic Writings of W Arthur Lewis (1980; ed. M Gersovitz).