This thesis re-examines selected short stories of Irish writer Mary Lavin, placing a particular focus on fiction she published from the early 1940s to the late 1950s. Drawing on extensive archival research into Lavin's unpublished correspondence, it uncovers how the transatlantic aspects of Lavin's biography intersect with key elements of the social and cultural history of mid-twentieth-century Ireland. It also provides vital new evidence to scholars through its explicit use of correspondence between Lavin's father, Tom Lavin, and his employers, the Bird family. The thesis shows how a mixture of autobiographical experience, social and political context and an emphathetic awareness of the significance of various cultural inheritances, inflects Lavin's realist style. Analysing important stories across the main span of her writing, the thesis contends that Lavin is a major figure, with a unique perspective on her times. Despite valuable early literary studies in the late 1970s and early 1980s, and some increasing attention during the 1990s, we have only recently begun to see a more sustained resurgence of interest in Lavin's fiction. While such a shift is welcome, this thesis argues that a perceived lack of complexity in Lavin's fiction still remains and needs to be challenged in order to reveal the true value of her oeuvre. The thesis offers a new analysis of Lavin's writing that tracks major themes, appraises her use of the novella form, and recognises the richness and significance of her contribution to the Irish literary canon. In taking a fresh look at Lavin's work, it thus prepares readers for a fuller understanding of the intricacies of her art.