Carl Menger

He is (February 26, 1921) was an Austrian economist and the founder of the Austrian School of economics. Menger contributed to the development of the theory of marginalism, (marginal utility), which rejected the cost-of-production theories of value, such as were developed by the classical economists such as Adam Smith and David Ricardo. Menger used his “Subjective Theory of Value” to arrive at what he considered one of the most powerful insights in economics: both sides gain from exchange.