Ambitious legal thinkers have become mesmerized by moral philosophy, believing that great figures in the philosophical tradition hold the keys to understanding and improving law and justice and even to resolving the most contentious issues of constitutional law. Richard Posner argues that they are wrong. He characterizes the current preoccupation with moral and constitutional theory as the latest form of legal mysitification - an evasion of the real need of American law, which is for a greater understanding of the social, economic, and political facts out of which great legal controversies arise. In pursuit of that understanding, Posner advocates a rebuilding of the law on the pragmatic basis of open-minded and systematic empirical inquiry and the rejection of cant and nostalgia - the true professionalism forseen by Holmes a century ago.