The study of industrial organization (IO) -- the analysis of the way firms compete with one another -- has become a key component of economics and of such related disciplines as finance, strategy, and marketing. This book provides an issue-driven introduction to industrial organization. Although formal in its approach, it is written in a way that requires only basic mathematical training. It includes a vast array of examples, from both within and outside the United States. This second edition has been thoroughly updated and revised. In addition to updated examples, this edition presents a more systematic treatment of public policy implications. It features added advanced sections, with analytical treatment of ideas previously presented verbally; and exercises, which allow for a deeper and more formal understanding of each topic. The new edition also includes an introduction to such empirical methods as demand estimation and equilibrium identification. Supplemental material is available online.