This essay focusses on functional analysis as a hitherto neglected part of intermediality studies. To begin with, the concept of ‘function’, some methodological difficulties concerning all Funktionsgeschichte and some ways of dealing with them are discussed. The main focus, however, is on an illustration of intermedial functional analysis in the field of twentieth-century musicalized fiction in English. After outlining some general connotations and hence functional potentials which music as fiction’s ‘Other’ has acquired in the course of history, the following functional dimensions are highlighted and related to the cultural and in particular aesthetic contexts of modernism and postmodernism: the musicalization of fiction a) as an expression and a reinforcement of the will to experimental transgressions of established (aesthetic) boundaries; b) as a means of following the (post-)modernist tendency towards self-referentiality and self-reflexivity; c) as a response to the (modernist) concern with a resensualization of art and with a-rational states of consciousness; d) as a response to the (post-)modernist feeling of an increased complexity and fragmentation of existence; and e) as a response to the (post-)modernist distrust of traditional, mimetic storytelling. To conclude, the problem of attributing specific functions of intermediality to historical contexts such as modernism and postmodernism is dealt with, and perspectives of future research are mentioned.