Panther and Thornburg focus on morphology and, more specifically, on the roles and interactions of metaphor and metonymy in creating polysemy in 'er' nouns. While they largely agree with Croft's (2002) views, they offer a more constrained characterisation of the notions of conceptual metonymy and contiguity. They accept the Lakoff and Johnson view of metaphor as a cross-domain mapping but define metonymy as an intra-domain mapping based on a contingent, i.e. non-necessary, and therefore cancellable relationship between two conceptual entities. The metonymic target is usually relatable to its source though it may become completely detached from its source, resulting in post-metonymy (Riemer's (2002) term). Panther and Thornburg's main thesis is that "-er" formations constitute a semantic network, having as their central sense that of 'professional human agent' embedded in a conceptual action schema that is multi-dimensional and whose parameters are scalar. The other senses of "-er" words are then metaphoric and metonymic extensions of this central sense. Moreover, the authors defend a non-syntactic approach to "-er" formations, considering e.g. both verb-based (baker) and noun-based formations (hatter) as realisations of the underlying action schema, where the former is derived from the verb "bake" in a direct, non-metonymic way, whereas the latter is formed from the patient role hat on the basis of the metonymy PARTICIPANT FOR ACTION. The scalarity of the defining properties of the central sense, i.e., a transfer of energy from a professional agent to a patient (as in "baker" or "hatter"), allows for such non-prototypical formations as "owner" and "dreamer". Consequently, the "-er" morpheme in "dreamer" does not have the prototypical sense of 'professional human agent,' but only that of 'someone who is inclined to dream.' The authors show that the processes of metaphor and metonymy operate equally well on the lexical stems and on the "-er" suffix itself. Concerning the latter, metonymic extensions of the "-er" suffix from agent account for instrument, location, and even patient referents of "-er" formations. Their analysis thus supports the view that derivational morphemes form symbolic units that are subject to the same conceptual operations of meaning extension as lexical morphemes. (René Dirven)