Persson examines a number of semantic theories from a functional point of view, i.e. he applies them systematically to actual language data. The two major theories compared are 'hardcore semantics', based on componential and truth-conditional analyses, and prototype theory, viewing categories as composed of fuzzy sets of central and peripheral examples. Persson suggests a synthesis in which both categorial concepts and typical attributes are assumed to play equally important roles. His functional analysis of concepts such as hyponymy reveals i) that co-hyponyms are not really exclusive in actual language use; ii) that synonymy is assumed to be a special type of hyponymy with fuzzy co-hyponyms; iii) that converse sentences with identical truth-conditions can be described (contrary to traditional assumptions) by means of a more perspective-oriented model. Throughout the book, P. emphasizes the overall importance of metaphors in both language and scientific models. (Rainer Schulze)