Covering core topics that explore the government's role in the economy, this textbook is intended for third or fourth year undergraduate students and first year graduate students. It includes markets, externalities, public goods, imperfect competition, asymmetric information and efficiency, and asymmetric information and income redistribution. A knowledge of intermediate microeconomics and basic calculus is assumed. Each chapter contains exercises at the end, whose solutions are available to instructors. Instructors' resource page: http://socserv.mcmaster.ca/leach/