This casebook presents a modern approach to understanding U.S. antitrust law, illuminating the economic analysis that dominates modern antitrust analysis in a straightforward way that minimizes technical jargon and makes the underlying economic concepts accessible to a broad audience. The cases are carefully edited to present the facts and issues clearly and succinctly, with the focus on extensive questions that probe those issues and show how to apply modern antitrust economic analysis to them. The result is a book that is quite compact, fewer than 800 pages, but covers the full waterfront of antitrust issues and generates plenty of multi-layered points and ideas to fill a class. All the recent Supreme Court antitrust cases are fully incorporated into the structure of the book, as are all the relevant agency guidelines. The merger section focuses on modern agency practices and merger theories, and selected cases that illustrate them, rather than on outdated Supreme Court cases that no longer describe current merger enforcement.