The principle of equality is one of the cornerstones of modern legal systems. Modern law is based on equality, and therefore assumed to stand in sharp contrast to the law of pre-modern, estates-based societies characterised by special legal regimes for particular groups or individuals. However, it is worth asking if this dichotomy can perhaps only be maintained if one looks solely at the fundamental postulates and the major codifications with their equality-orientated system formations. ‘Modernity’, too, is highly socially differentiated and continues or transforms ‘pre-modern’ distinctions to a not inconsiderable extent. All of this is often reflected in special rules created by the state or by the groups themselves – even if, in the latter case, they are often not recognised as law. In this volume, the term ‘diversity’ denotes constellations of social difference that are relevant to normativity. This understanding of diversity only partially overlaps with the categories of postmodern diversity discourses. Rather, this volume’s central questions ask what social differences are relevant to normativity, to what extent and in what respect. Or, to relate it more specifically to the relationship between law and diversity: which social differences also make a difference to the law? A comparative look at European and non-European developments provides a broader perspective on these issues. In this context, Latin America is a particularly fruitful field of investigation. On the one hand, a translation of European legal traditions already took place during the colonial period and, after independence, Latin American states striving for modernity often took recourse to European legal ideas and regulatory models. On the other hand, the legacy of the colonial past continued to have a formative influence, and the social differentiation to which the law had to respond was largely different from that in European societies. To ensure that bringing together European and Latin American perspectives did not result in a series of mere juxtapositions, the contributions on the development of a specific national legal system are accompanied by comments written by experts on other national legal systems. These comments, firstly, outline the comparative development in a different state and, secondly, highlight differences and similarities. European and Latin American authors alternate. The period under discussion is the last 200 years. In volume 1, the authors deal with fundamental questions of law and diversity. Further volumes on public law, private law and criminal law will follow.