This volume contains a selection of the most important articles on the issue of the evolution of the common law. The notion that evolutionary forces would lead to common law efficiency has been very influential in the study of the economics of law. Even those scholars who do not believe that the law is efficient will find it useful to consider the evolutionary forces identified in this volume.In an even-handed approach, Professor Rubin has selected not only articles which advance the hypothesis of efficient evolution, but also those which claim that the evolutionary process is not efficient. Further articles show that the process is indeed sometimes efficient and sometimes not, and identify those conditions which bring about more of less efficiency in the evolution of law. This authoritative collection will be useful to anyone who is concerned with the sources of efficiency and inefficiency in the law, as well as to scholars pursuing research in this area.