I shall consider here the role of topical content in the rhetoric of Classic music, using Mozart's keyboard sonatas by way of illustration. The term 'topic' here signifies a subject to be incorporated in a discourse. A topic can be a style, a type, a figure, a process or a plan of action. Topics can be intra-musical-elements of the language of music-or extra-musical taken from other media of expression. The connection between these two aspects of topical content has a long history. Music, in its relationship to the temporal artspoetry, drama and choreography-has been something of a chameleon, if not an actual parasite. Throughout its history Western music has repeatedly been taken up by the language and theatrical arts as a means of intensification, to elevate and sustain the effect of the word or gesture. But as music joins with word or gesture it gradually incorporates its own syntax, its idiomatic elaborations to the point that the word or gesture is absorbed into the play of musical rhetoric, especially in extensions and elaborations. The actual presence of the 'host' (that is, the word or gesture) disappears, but its configuration remains in the contour and the form of the music-a process comparable to the shape that is given to the finished jewel in the lost wax process. This back-and-forth process, in which music is borrowed and then takes over, finally to be simplified once again when it becomes too elaborate, has taken place a number of times-in plainsong, in medieval polyphony, in the Renaissance motet and madrigal, and in Italian opera of the 18th and 19th centuries. These processes bespeak apt connections between music and other media of expression, both in syntactic ways and in the sense of what is being communicated. The influences work in both directions-from the image, gesture or idea to musical syntax and vice versa. That is, musical syntax can enhance the word or gesture; on the other hand, the suggestion or the implication of the image, word or gesture can give colour and enriched content to musical syntax. The syntactical make-up of Classic music lends itself aptly to the interplay of musical processes and topical references. In the Classic style, the precise trim of cadential formulas, rhythmic groupings, clear articulations, transparent textures and orderly key schemes allow a composer to etch sharply with figures that are neatly and closely spaced, to spin out a rhetoric that is essentially comic and witty in its underlying tone. This attitude is embodied particularly in the rapid shifts of topic, of affective stance, that are so often heard in late 18thcentury music. Wilhelm Fischer characterized Classic music as incorporating contrast on the smallest scale.' A biting comment on an aria of Paisiello in 1778 is addressed to the prevailing Italian penchant for mixing topics. The writer, Goudar, says: