The starting point for this book is the ‘crisis’ in labour law which engendered a new wave of regulation for ‘precarious work’. This book investigates the particular notion of precarious work and its regulation, but more importantly, it uses the opportunity of the ‘crisis’ to explore the notion of precariousness or vulnerability in employment relationships more generally. It is argued in this book that this notion of vulnerability has been under-theorized in the labour law literature and that this under-theorization extends to the literature on the design of regulation for precarious work. This lack of theorization of the nature of vulnerability has comprised two elements. First, there has been too much concentration in labour law policy and practice on external forces which direct economic and social change, rather than giving adequate consideration to the personal dimensions of vulnerability. Second, labour law theories tend to be underscored by notions of the liberal subject: autonomous, rational and independent beings. It is argued that a shift in focus to workers as ‘vulnerable subjects’ in all their complexity has a much greater potential to ensure the ability of regulation (within and outside precarious work) to really address their needs. The first part of this book investigates the different views of the nature of vulnerability in employment relationships, and how these different views affect the goals of regulation (for precarious work). Four different theoretical standpoints are explored: (1) classical labour law, (2) efficiency views of regulation, (3) social law and (4) the vulnerable subject theory. It is argued that the first two theoretical standpoints represent an external view of vulnerability which is dominated by the liberal subject approach. The latter two positions present views which start instead from an exploration of the nature and cause of personal vulnerability and what that means for the regulation of work. The second part of this book looks at the practical application of these findings. This second part starts with regulation for precarious work in practice and looks at how far this regulation complies with the vulnerable subject approach. This is followed by two case studies on the regulation of specific precarious labour market groups: (1) temporary agency work and (2) domestic work. Within these sections it is suggested that legislation which meets the needs of the vulnerable subject framework and which starts from the vulnerable subject has the greatest potential for the future of employment regulation.