Sir John Richard Hicks (8 April 1904 – 20 May 1989) was a British economist

Economist

An economist is a professional in the social science discipline of economics. The individual may also study, develop, and apply theories and concepts from economics and write about economic policy...

 and one of the most important and influential economists of the twentieth century. The most familiar of his many contributions in the field of economics were his statement of consumer demand theory

Consumer theory

Consumer choice is a theory of microeconomics that relates preferences for consumption goods and services to consumption expenditures and ultimately to consumer demand curves. The link between personal preferences, consumption, and the demand curve is one of the most closely studied relations in...

 in microeconomics

Microeconomics

Microeconomics is a branch of economics that studies the behavior of how the individual modern household and firms make decisions to allocate limited resources. Typically, it applies to markets where goods or services are being bought and sold...

, and the IS/LM model

IS/LM model

The IS/LM model is a macroeconomic tool that demonstrates the relationship between interest rates and real output in the goods and services market and the money market...

 (1937), which summarised a Keynesian view of macroeconomics

Macroeconomics

Macroeconomics is a branch of economics dealing with the performance, structure, behavior, and decision-making of the whole economy. This includes a national, regional, or global economy...

. His book Value and Capital

Value and Capital

Value and Capital is a book by the British economist John Richard Hicks, published in 1939. It is considered a classic exposition of microeconomic theory...

(1939) significantly extended general-equilibrium and value theory.