This book presents recent developments in the economics of asymmetric information. The problems of selection and moral hazard, with hidden actions or hidden information, are introduced by examining how they affect the market for investment finance. The ideas are then used to analyse the market for insurance, signalling and screening models of education, efficiency wages, industrial regulation, public procurement and auctions. Coverage is thorough while avoiding excessive mathematical detail. Diagrams and verbal reasoning make the ideas accessible to intermediate level undergraduate students and beyond.