Interrogating the much-cherished concept of "poetic thinking," this book focuses on what interview and draft materials reveal of how poets actually do think, when in the act of writing. The interviews confirm what findings from cognitive science and linguistics make clear: we rarely know exactly what words we are going to say, until we have said them. Suddenness and the Composition of Poetic Thought draws out the implications of a radically curtailed view of consciousness on how we understand the drafting and revision of lines of poetry, with implications for our theorisation of the composition of prose. Henrich von Kleist's assertion that "it is not we, but a certain condition of ours which knows" emerges as central to this reassessment of the nature of the written word. Employing an extensive archive of interview materials with major Anglophone poets, discussing how they think in the moments of composition, this book also provides a lucid account of the links between poetic composition and live performative thinking in the contexts of Romantic compositional practice and the early (pre)textual history of ancient Greek epic. A transdisciplinary study at the crossroads of philosophy, cognitive psychology, literary studies, and linguistics, this book reconceptualizes the wellsprings of poetic thought and advances our understanding of thinking's complex but vital link to improvised speech.