This chapter investigates Shelley’s fascination with issues of communication, especially his engagement with concepts of action at a distance, “the action of one object on another regardless of the presence or absence of an intervening medium” (Oxford English Dictionary). Shelley’s attempts to overcome distances of space and time were a feature of his correspondence, especially during his years in Italy. Action at a distance also informs his representation of a materialized physical universe in early works like Queen Mab (1813) and provides a foundation for his later accounts of political communication in The Mask of Anarchy (1819). I suggest that Shelley’s account of unmediated action at a distance coalesces with more recent treatments of matter and mediation in quantum physics and especially in Karen Barad’s account of material entanglements in which “matter [is] a dynamic and shifting entanglement of relations, rather than a property of things.” Shelley’s poetry itself functions as a form of Baradian apparatus with the facility to offer “agential cuts,” providing moments of insight within intra-active material systems. In these poems, Shelley presents the universe as one continuous material system, which enables unmediated communication across any distance, and which at times of political crisis enables instantaneous solidarity and resistance.