There are a number of ways to tell the story of the change in American tort law that occurred in the nineteenth and twentieth centuries. Some, like John Witt, Lawrence Friedman, and Mort Horwitz, focus on changes in material conditions. Others, like Richard Posner, Charles Gregory, and Robert Rabin, focus on changes in intellectual or doctrinal beliefs about the nature of tort law, and the best mix of rules to achieve its ends.