Designed to integrate economic principles into a traditional contracts course. The cases and materials consider reasons why some contracts should not be enforced, where enforcement might lead to inefficient results due to externalities, mistake, or lack of capacity or consideration. Introduces the theory of efficient breach and applying that theory to issues of impracticability and impossibility. Considers various permutations of the traditional remedies for breach and the limitations on recovery of damages. The final section considers duress and unconscionability and offers economic rationales for not enforcing agreements into which parties have voluntarily entered.