This thesis uses the popular genre of detective fiction to explore the context of the heyday of the crime genre: the Golden Age. This sub-genre, best known for producing Agatha Christie, spanned the complicated history of Britain involving the Great Depression, two World Wars and huge changes to class structure. It is for these reasons that the Golden Age is such a pivotal period for changing notions of British identity. Through the very British Christie and the less well known New Zealander, Ngaio Marsh, expressions of national identity are explored as well as how the colonial fits in. Focusing heavily on the authors and their own personal experiences and views, this thesis is divided into four chapters to further break down how the Golden Age period affected its citizens and why this detective fiction held such a wide appeal. Chapter one explores gender roles and how Golden Age authors both conformed to them through their choice in detectives, yet also how they naturally resisted some through their own public image. Chapter two then examines the issue of class and how Golden Age detective fiction portrayed the changes. Contrary to popular criticism, Christie and Marsh were surprisingly progressive and forward thinking on this subject. Chapter three considers how both authors employed setting to emphasise these changes. Both Christie and Marsh used foreign settings to highlight British society and its flaws, and Marsh used her New Zealand settings to consider the relationship between Britain and her home. The final chapter will consider why Golden Age detective fiction was so popular: what was the appeal? For a period of violence and uncertainty, why were people drawn to crime fiction involving sometimes gruesome death? The appeal lay, and still does, in the puzzle: the game that diverted readers from their own problems. Golden Age fiction may have been highly formulaic and predictable, but it was also highly artificial and self-referential. This was a clever and diverting fiction that has been constantly underestimated by critics and deserves further study.