Consumers routinely enter into long-term contracts with providers of goods and services - from credit cards, mortgages, cell phones, insurance, TV, and internet services to household appliances, theatre and sports events, health clubs, magazine subscriptions, transportation, and more. Across these consumer markets certain design features of contracts are recurrent, and puzzling. Why do sellers design contracts to provide short-term benefits and impose long-term costs? Why are low introductory prices so common? Why are the contracts themselves so complex, with numerous fees and interest rates,...