In her 1955 novel A World of Love, Elizabeth Bowen considered the effects of a fifty-year period in which the outbreak of two world wars had reconfigured radically the expected course of personal and national history. Those alive at the mid-century, she observed, were consequently more aware than ever before of ‘unlived lives’: the opportunities they might otherwise have had, the people they might have become in a lifetime of peace, and the decades they might have spent with the war-dead had they too survived. As Andrew H. Miller has shown, engagement with those counterfactual speculations with which lived experience often finds itself supplemented is not a feature unique to mid-twentieth century British fiction. What has been overlooked by scholarship, however, is the significance of the connection drawn by a range of novelists in the twentieth century between the long-term psychological effects of aberrations like world war and genocide, and the observed tendency of individuals to incorporate ‘unlived’ experiences into their identities and personal histories. Bringing together three authors whose works treat collectively life lived in the aftermath of the American Civil War, the First World War and the Second World War – Henry James (1843-1916), Elizabeth Bowen (1899-1973) and Kazuo Ishiguro (1954-) – this thesis takes up the unexplored influence of ‘unlived lives’ on the form and content of twentieth century literature, and examines how each of these writers conceived of the wars of the modern era as posing challenges to the models of personal and experiential fulfilment through which sense of self was typically established. The texts around which my work is organised include James’s The Portrait of a Lady (1881/2), as a pivot into modernity, ‘Maud-Evelyn’ (1900) and selected Prefaces to the New York Edition (1907-9); Bowen’s The Hotel (1927), The Heat of the Day (1949) and A World of Love (1955); and Ishiguro’s An Artist of the Floating World (1986) and The Remains of the Day (1989). The thesis ultimately aims to establish ‘unlived lives’ as a vital area of inquiry for scholarship examining the development and representational ambitions of twentieth century narrative.