This volume presents a sociological theory that includes possibilities for analyzing legal theory as well as other intricate constructs of thought. Legal theory is regarded as a reflective performance of the legal system. The term "differentiation of law" refers to the perspective that enables reflection within the legal system itself and its observation from the outside. It denotes a historical process that depends on the evolution of the societal system. In the theoretical language of sociology, the evolution of law, the differentiation of a specific functional system for law, its relationship to everyday interactions and conflicts can be addressed, and above all, of course, the function of law.