This is the first of two articles attempting a literary assessment of Valerius Flaccus' Argonautica. It will examine the poem from the beginning to 3. 474, and its successor will cover from 4. 58 to the end. Thus, there will be no overlap with matter already printed in my article, ‘The Hylas Episode in Valerius Flaccus' Argonautica’ (C.Q. N.S. xiii [1963], 260–7), and instances of the poet's application in other sections of the same literary principles as in the Hylas story may now be dealt with summarily. The episodes are treated in order of importance rather than of occurrence, with the emphasis at present on broad outlines rather than linguistic or metrical minutiae. Even within these limitations, this assessment does not aim at exhaustiveness. Where a section of the Argonautica is unremarkable and throws little light on Valerius' poetic method, pro re pauca loquar.