Structuring the Cosmos in Valerius Flaccus's Argonautica explores motifs of cosmology, meteorology, and discordia in the Flavian epic. It demonstrates how Valerius, especially by means of intertextual allusion, draws on theories of natural science and philosophy (an eclectic mix of Stoicism, Epicureanism, and Empedoclean doctrine, on an ethical as well as a cosmological level) to construct an unstable cosmos that is, on multiple levels, both prone to dissolution and a breeding ground for cycles of civil war. The book argues that Valerius's intertextual practices can be read as a form of “cosmopoetics,” in that he uses language, images, and ideas from earlier literature to collectively build a picture of the cosmos's operation within his poem. At the study's heart and, it is argued, of Valerius's epic are the elements of air and fire, as aspects of nature, as personified mythological beings, and as active cosmic forces functioning in parallel across physical and conceptual strata (from the subterranean to the celestial; from the social to the macrocosmic). Looking to move beyond “pessimistic” and “recuperative” readings of the epic, Structuring the Cosmos reevaluates Valerius's engagement with the Flavian literary, philosophical, and historical climate, especially as a poet of civil war.