Case, a system which marks the relationships between words in a sentence, is fundamental to every language. This accessible textbook introduces the various approaches to case that have been proposed in modern linguistics, looking at how different syntactic theories have accounted for the distribution of case across languages. Each chapter contains practical exercises, encouraging students to engage with the ideas discussed. Drawing on data from many world languages and pooling together a variety of perspectives, Theories of Case is essential reading for all those studying this important area of linguistics.