The Introduction overviews the context of this study, which includes an explanation of why irregular migration and health are particularly urgent and interconnected areas of human rights enquiry in the twenty-first century. The question guiding this research is identified in: Are international and European human rights frameworks sufficiently equipped to interpret and develop the right to health of irregular migrants towards meaningful levels of health care provision and health promotion? Furthermore, this chapter introduces some preliminary definitions and draws the contours of the analysis of the book. Finally, it contains the plan/structure of the book.