Undocumented Migrants and their Everyday Lives: The Case of Finland discusses the processes and practices through which migrants become undocumented; what their everyday lives consist of; which local, national, and international policies and practices affect them; and how they deal with them. In addition, the book reflects on how research on undocumented migrants can best be conducted using quantitative, qualitative, and mixed methods, and reflects on research ethics and methodologies. The empirical focus of the book is Finland and, more broadly, the European Union (EU), but the themes connect to a broader geographical scope.The topic of irregular migration and undocumented migrants is becoming increasingly important in Europe. The book asks who these undocumented migrants are; what their everyday lives are like, what key issues concern them; and how the society regards them—particularly in Finland. Among the key themes addressed are the asylum processes and their failures; the housing, employment, and social networks of undocumented migrants; their migration journeys to, within, and beyond Finland; their healthcare; and their uses of the internet and social media. This introductory chapter outlines the book, describes the Finnish context, and reviews the literature concerning the emergence of the undocumented migrant phenomenon.