This chapter explores poets’ letters as ‘an art form’ in the post-Romantic period, exploring the bearing of poets’ letters on their poems (and vice versa). It reflects on the key role played by epistolary dialogue in the creation and circulation of poetry in the modern period, documenting the ways poets first launched poems in letters to friends, and used letters to sketch out their ideas about poetry and poetics. It comment on the practice of a number of nineteenth-century poets who used letters to launch ideas about their poetry (including Keats, the Brownings, Hopkins and Emily Dickinson), before moving on to consider the equally crucial role of correspondence in the work of twentieth-century poets (including Bishop, Lowell, Marianne Moore, Ted Hughes, Sylvia Plath, and Philip Larkin). In offering a survey of this broad epistolary territory, it also outlines an idea of an epistolary poetics.