Stefan Müller has written an extensive study of a large range of German constructions from the perspective of head-driven phrase structure grammar (HPSG). For a theoretical work, it is notable for its scale, for its extensive use of current material from corpora, and for its welcome attention to the descriptive literature. Furthermore, the analyses can be tested on Müller's prolog implementation of HPSG, which runs at http://www.dfki.de/~stefan/. This is a very extensive fragment of German, involving thousands of words of different classes, raising and control verbs, passives, verb particle constructions, the “third“ construction, modal flip (Oberfeldumstellung), several sorts of relative clauses, extraposition, complex fronting, semifree word order in the Mittelfeld, scope ambiguities, and more. It is unusual to find this all in a single implementation, and the work is unique in being made available on the web. Müller's web page also contains errata for this book and examples.