Law can be viewed as a body of rules and legal sanctions that channel behavior in socially desirable directions — for example, by encouraging individuals to take proper precautions to prevent accidents or by discouraging competitors from colluding to raise prices. The incentives created by the legal system are thus a natural subject of study by economists. Moreover, given the importance of law to the welfare of societies, the economic analysis of law merits prominent treatment as a subdiscipline of economics. Our hope is that this two volume Handbook will foster the study of the legal system by economists.