Chapter 1 is devoted to an introduction into the topic of case in general and its relation to semantics in particular. It illustrates a range of case alternations in different languages, showing, on the intuitive level, the ways in which the form of the noun affects sentential meaning. The inherently relational nature of case is discussed, and the distinction is made between abstract, morphological and morpho-syntactic case. The chapter further addresses the classification of cases into structural/configurational, inherent, lexical and semantic. Examples of several case systems in different languages of the world are provided, and the distinction between ergative-absolutive and nominative-accusative languages is introduced. The chapter also briefly illustrates the interrelation between case-marking and theta-role assignment, a phenomenon that is familiar primarily from the literature on inherent case. Finally, the structure of the following chapters is outlined.