This chapter addresses the relationship between Shelley’s epic theory and practice with reference notably to Laon and Cythna and “A Defence of Poetry”, as well as Queen Mab and Prometheus Unbound. The essay shows how Laon and Cythna breaks with epic tradition – and exceeds Shelley’s own theoretical account of the genre – in finding creative solutions to the problem of how to link past, present, and future, as well as the local and the universal, without didacticism or what Shelley in the ‘Defence’ calls the ‘gross’ sense of prophecy: a foretelling of the future. I contend that Shelley’s epic poetry does not seek to recuperate past moments of social coherence to guide and unify the present or predict the future so much as to leave space for not knowing what will come. Shelley’s experimental epics regard a hopeful uncertainty as, paradoxically, the only certain means of reform.