In the twentieth century, the boundaries between different literary genres started to be questioned, raising a discussion about the various narrative modes of factual and fictional discourses. Moving on from the limited traditional studies of genre definitions, this book argues that the borders between these two types of discourse depend on complex issues of epistemology, literary traditions and social and political constraints. This study attempts a systematic and specific analysis of how literary works, and in particular documentary ones, where the borders are more difficult to define, can be classified as factual or fictional. The book deals with several areas of discourse, including history, travel tales, autobiography and reportage, and opens up perspectives on the very different ways in which documentary works make use of the inescapable presence of both factual and fictional elements.