Over the past twenty years, the study of industrial organization -- the analysis of imperfectly competitive markets -- has grown from a niche area of microeconomics to a key component of economics and of related disciplines such as finance, strategy, and marketing. This book provides an issue-driven introduction to industrial organization. It includes a vast array of examples, from both within and outside the United States. While formal in its approach, the book is written in a way that requires only basic mathematical training. Supplemental materials posted on the Web make more extensive use of algebra and calculus.