In this Introduction I begin by considering the interdisciplinary development of affect theory, and how it has been seen as splitting into two camps: that of the ‘cognitivists’, who see affect as involving emotion and cognition, and that of the ‘noncognitivists’ who don’t. I argue for a concept of literary affect that is neither strictly cognitivist nor noncognitivist. Through readings of Spinoza, Sylvan Tomkins, and Deleuze I show how they provide the basis for developing such a concept of affect, and I go on to develop a literary aspect to it through readings of a range of literature, criticism, and theory, including works by Longinus, Milton, Edmund Burke, Denise Riley, T. S. Eliot, Raymond Williams, William S. Burroughs, Virginia Woolf, and Lyn Hejinian. After giving examples of how a concept of literary affect is useful for reading texts, I outline the rationales of this book’s three sections while indicating how the sections’ chapters complement each other.