Originally published in 1890, "Principles of Economics" was the first text to bring together the theories of supply and demand, marginal utility, and cost of production into a coherent whole. It introduced a number of new concepts which have formed the building blocks of modern microeconomics and underpin modern-day business strategy. Explored concepts include: elasticity of demand--how consumer demand for a good or service is affected by a change in its price; consumer surplus--the difference between the maximum price a consumer is willing to pay and the price that they actually pay; and quasi-rent--the profit made in the short-term from a product/innovation due to a reduction in supply. The book also unveils the theory of supply and demand, emphasizing that the price and output of goods are determined by the intersection of supply and demand curves which act like scissor blades, and not by the theory of value. In this classic work, Marshall builds on the works of other great thinkers in the Classical School such as Adam Smith, David Ricardo, Thomas Robert Malthus, and John Stuart Mill, but shifts the emphasis, for the first time, away from the market to the individual and the study of human behavior. This re-issued classic contains a new introduction by Professor Peter Groenewegen who explores the profound impact that this critical work has had on economic and business thinking.