This thesis examines and explores twentieth century literary representations of American masculinity at war. It aims to demonstrate the manner in which American novels responding to the First and Second World Wars and the Vietnam conflict reflect symbolic, mythic and material anxieties regarding America‟s masculine identities. The thesis examines in particular the pervasive myth of the American Adam and its influence on behaviours, ideologies and narrative. Each text and each conflict operates under the influence of Adamic myth. I argue that prose fiction offers a space in which to scrutinise, engage and ultimately resist such mythic singularity. The incorporation of gender theory into such a study provides an original critical perspective with which to read crucial artistic responses to major events of the American twentieth century. Its central arguments engage with anxieties existing between ideological representations of hegemonic American masculinity and the graphic truth of experience for the corporeal and psychological subject. As well as thematic aspects of the literature, the thesis analyses shifts in narrative technique and the manner in which they reflect the growth and pluralising of wider narratives within the fields of modernism, American naturalism and postmodernism. The contemporary era is marked by commemoration and reflection regarding twentieth century conflict and by anxiety regarding the unstable post 9/11 world. In addition to this, there is resurgence in scholarly, political and popular interest in gender and its representation. These factors mean that this is a timely and vital study that reflects on literary history and current literary debates. The authors and their work in this thesis are considered in chronological order and cover a significant part of the American twentieth century. Chapter one examines John Dos Passos‟ Three Soldiers and Ernest Hemingway‟s A Farewell to Arms. Chapter two engages with two Pacific war novels; Norman Mailer‟s The Naked and the Dead and James Jones‟ The Thin Red Line. Chapter three explores post-war existential angst and early postmodernism in Joseph Heller‟s Catch-22 and Kurt Vonnegut‟s Slaughterhouse-Five. The final chapter offers analysis of Larry Heinemann‟s Close Quarters and Paco’s Story and Tim O‟Brien‟s Going After Cacciato and The Things They Carried.