An Introduction to the Functioning of the Economy and the Power and Breadth of Economics. Reviewers tell us that Case/Fair/Oster is one of the all-time bestselling Principles of Economics texts because they trust it to be clear, thorough, and complete. Readers of Principles of Microeconomics, Twelfth Edition come away with a basic understanding of how market economies function, an appreciation for the things they do well, and a sense of things they do poorly. With the latest research and added exercises, readers begin to learn the art and science of economic thinking and start to look at some policy and even personal decisions in a different way.