Jean-Baptiste Say was born in Lyons, and was the first to teach Political Economy in France. He was a classical writer and is most commonly associated with "Say's Law", which simply states that supply creates its own demand. Along with other clas sical writers of his time, Say felt that overproduction was impossible by its very nature, since all value relations were relative. In Say's Law, you can see the implicit assumptions of flexible prices and wages. According to Say, this law holds in t he long-run and the short-run. It is the short-run version that both Malthus and Keynes later attacked.

Say was among the first economists to question the commonly held belief in the labor theory of value. He believed the value of a good derived from its utility to the user and not from the labor spent in producing the good.

According to Karl Marx, economist Heinrich Friedrich Storch exposed the error of Say's interpretation of production and consumption as identical. According to Storch, " a people does not consume its entire product, but also creates means of production, e tc., fixed capital, etc." According to Marx, Say was "a businessman who popularized and vulgarized the doctrines of Adam Smith in his,"Traité d'économie politique". This book was translated into English and used as a textbook in En gland and the United States.

There has been some question regarding the authorship of Say's Law. Though Jean-Baptiste Say did in fact propound this idea, it was James Mill (father of John Stuart Mill) who first used the words: "supply creates its own demand".

Works by Jean-Baptiste Say:

• Traité d'économie politique