Taking the idea that a literary reading of Olivia Manning's work based on her great novelistic skill rather than on her life is possible as a starting point, this thesis explores how Manning's The Balkan Trilogy and The Levant Trilogy engage with some of the great debates of the twentieth century. This thesis examines Manning's narration of World War II focusing on the figure of the war narrator, on the representation of place and space in the context of war and the end of British imperialism, and on the portrayal of sexuality and gender in wartime from a literary rather than autobiographical point of view. The introductory chapter offers a review of the critical attention Manning has received up to present. Chapter two analyses Manning as a Second World War writer and examines the different strategies she used to convey war. The different fictional witnesses of war in The Balkan Trilogy and The Levant Trilogy, both male and female, combatant and non-combatant, are analysed in order to see who portrays war more comprehensively. Chapter three offers an analysis of the portrayal of place and travelling in wartime, and compares different characters' responses to their surroundings in Manning's World War II trilogies. Furthermore, this chapter analyses Manning's representation of Romania, Greece and Egypt and of its native people, taking into account that these countries were (or had been) territories under the influence of the former British Empire. Chapter four explores the different ways in which war alters gender roles in Manning's war fiction. This chapter studies how the public and domestic spheres interact in Manning's The Balkan Trilogy and The Levant Trilogy. To do this, I examine Manning's portrayal of sexuality, marriage, home and motherhood to analyse the different ways in which they are altered by the war.