Sebastian Hofmann's monograph is bulit around two themes: the grammatical status of complex prepositions (Chapter 3) and the applicability of grammaticalization theory as a framework for their analysis (Chapters 4, 5). Complex prepositions, narrowed down to preposition-noun-preposition or PNP-constructions, are an excellent choice (although Hofmann somewhat simplifies his task by choosing sequences whose noun component is not "any noun" but a singular one without a(n)/the, presumably as a sign of advanced decategorization). They extend the existing repertory of simple prepositions quite significantly both in quantity and quality and if Hofmann's (and other authors') effort to have them "officially recognized" succeeds, it may possibly contribute to a more sweeping recognition of multi-word forms in other word classes. The monograph is also interesting from the methodological point of view: it may be seen as a dialogue between two different paradigms of linguistic thinking: rule-based argumentation in the generative grammar mould (represented by Seppänen et al.using constructed examples) and Hofmann's empirical, usage-based and quantitative, approach relying on extensive corpus data.