Case characterizes distribution of nominals within a sentence (abstract Case), which can be reflected in morphological marking on nominals (morphological case). A related phenomenon of agreement characterizes a structural relation between a nominal and a functional category, which is morphologically manifested on the functional category. This Element examines how Case/case and agreement phenomena are derived, focusing on the syntactic operations involved. The Element discusses the types of morphological case, as well as the concept of abstract Case, starting with the seminal works of Vergnaud and Chomsky, followed by the theories of unification of Case/case and agreement, specifically the Spec-Head configuration and the operation Agree. Demonstrating empirical shortcomings of such unification, alternative approaches are considered (Dependent Case Theory and morphological approaches to agreement), illustrating their empirical and conceptual challenges. Ultimately, the Element sketches a theory of Case/case and agreement using independently motivated concepts of copy interpretation and labeling.