Economics is a social science concerned chiefly with description and analysis of the production, distribution, and consumption of goods and services. The word comes from the Ancient Greek oikonomia (management of a household).
Adam Smith's The Wealth of Nations (1776) has been described as "the effective birth of economics as a separate discipline." Smith identified land, labour and capital as the three factors of production and the major contributors to a nation's wealth, as distinct from the previously-held idea that only agriculture was productive.
The work of Keynes in the 1930s was a landmark in the development of economics, and he is considered by many to be the most influential economist of the 20th century.