This chapter introduces some basic notions and theoretical background. First is a definitional description of Standard German, the language investigated in the book, followed by a review of the constituents of the prosodic hierarchy and the domains of phonological alternations and processes, as well as the recursive structure of the higher-level constituents, the ones at the interface with morphology, syntax and semantics. After that background-setting exposition, Optimality Theory (OT), the theoretical framework used in the book, is described minimally, for scholars not familiar with this approach. The chapter also contains a short description of the remainder of the book, as well as a survey of the conventions used. It ends with some remarks about what is not part of the book.