The 12th Edition continues to evolve while remaining anchored to this casebook's core commitments. Throughout its long history, this casebook has relied on classic cases to capture the fundamental principles of contract law. It has also showed how these cases continue to set the framework for modern analysis. This new edition preserves and builds upon the book's distinctive character, especially its use of canonical cases and its sensitivity to the history. The newly added cases show how the basic principles of contract law continue to evolve, such as courts application of frustration of purpose and impracticability to the challenges raised by COVID. As before, this edition eschews any distinctive take on the law of contracts and thus allows each teacher using the book a broad range of choice on what to bring in to channel or expand classroom discussion. The book incorporates the recently approved Restatement on Consumer Contracts A significant number of new cases have been added. Cases from the last century that do not break new ground have been eliminated and the overall length of the book has been reduced.