Alfred Marshall was a torrent force in British economics for 34 years, until his death in 1924. An anchor to neoclassic economists, he was especially influential in the lives of two of his most famous students: John Maynard Keynes and Joan Robinson.Whenever economists today look to supply and demand in order to understand the shift in the price or the quantities bought and produced of their products, then they owe it to Alfred Marshall.In his book Principles of Economics, Alfred Marshall took a closer, more detailed look at the various market structures, commonly known as micro economics. In this book, Marshall explained how the demand and supply curves, like the blades of a pair of scissors, come together to tailor the best conditions for a market. At the intersection of the demand and supply curves, an equilibrium price is formed. There the quantities demanded can happily equal the quantity supplied…and they live happily ever after, or until disequilibrium sets in again. Alfred Marshall was concerned that time was an important factor in how the markets adjusted to demand and supply. Consequently, he introduced the idea of three periods. First is the market period, the amount of time for which the stock of a commodity is fixed. Second, the short period is the time in which the supply can be increased by adding labor and other inputs but not by adding capital, or as Marshall preferred to term it. Third, the long period is the amount of time taken for capital (appliances) to be increased. Alfred Marshall was also famous for his focus on human behavior. He believed that an economy evolves according to technology and societal values. According to Marshall, changing society changes its economy. Others topics include the theory of utility, elasticity of demand, and rent seeking. Due to his mathematical background, Alfred Marshall rarely expressed a thought or a theory without thorough examination, footnotes, graphs, and statistics. You will find that he was sort of a romantic. For marrying his wife, Mary Paley, a former student of his, Alfred Marshall had to give up his fellowship at Saint John. But it paid off when she began co-authoring books with him.Alfred Marshall was known for many theories, including the Theory of Demand, Theory of Production, Cost of Production and Supply, Theory of Price Determination and Prices that Deviate from Cost of Production.