A concern with the methods and style of praise and blame recurs, unsurprisingly, throughout Callimachus' Iambi. The iambos is the aggressive mode par excellence, and Callimachus is the most generically-conscious of poets; whether he is writing hymns, aetiological elegy or funerary epigram he is always overtly engaged with the history and development of the literary form in which he operates. The nature of iambic poetry is, however, the explicit subject of two poems in particular, Iambus 1 and Iambus 13, which thus have a special claim to be considered ‘programmatic’. The thirteenth Iambus returns to the choliambic metre of the first four poems, the metre most associated with Hipponax, who appears himself in the first Iambus as the authorising ‘voice’ for these poems, and is apparently spoken in the voice of the poet who to some extent takes up again the themes of Iambus 1 (and indeed of Aitia fr.1); thus the temptation to see a ‘closed’ poetry book, framed by these two poems, is very strong.