the enforcement of labour law in cross-border worker situations increasingly gains attention at eu and member state level. especially due to the eu enlargements in 2004 and 2007 and the huge wage differences that exist across the eu member states have boosted exercising the free movement of workers and the posting of workers. these developments have raised the awareness that enforcement of labour law is crucial and should be put high on the eu's and member states' agenda. this book addresses an important question: in which ways and to what extent do eu rules and eu case law exert influence on the dutch, german, and swedish methods to monitor and enforce labour law in transnational situations? this question is examined for labour law in terms of minimum wages, minimum holiday pay, and minimum holiday allowances. moreover, a sectoral approach by taking the construction and the temporary agency work sector as examples provides insights into the enforcement strategies of the social partners. there is no role for the eu (institutions) to enforce workers' rights at member state level. member states themselves are responsible for enforcing the rights foreign workers derive from eu law. at member state level, three enforcement methods can be distinguished: the judicial (civil or labour court), the industrial relations (social partners), and the administrative enforcement (labour inspectors) method. the ecj has established jurisprudential requirements (the principles of equivalence and effectiveness) that serve as a floor for member state enforcement methods. besides, to a certain extent eu rules provide guidance on how member state enforcement methods should be construed, of which the in april/may 2014 adopted posted workers enforcement directive and the union workers enforcement directive are two recent examples. while this 'floor' seems to be easily met by the enforcement methods available at member state level, difficulties arise in the context of the posting of workers, a form of worker mobility that is based on the freedom to provide services. the right of the employer to provide cross-border services puts a ceiling on the member state possibilities to adequately monitor and enforce the rights of posted workers. as a result, due to the floor and ceiling caused by eu rules and eu case law, it becomes a balancing act for member states' enforcement methods. this study shows the main differences as well as the similarities that exist between the enforcement methods in these countries. it makes clear that enforcement of the rights of workers in cross-border situations has become increasingly difficult for member states. this book provides an in-depth overview of how germany, the netherlands, and sweden monitor and enforce the rights of mobile workers by describing the three enforcement methods available in all three countries. enforcement of labour law does only work if all three enforcement methods are used. this study makes clear that there is no one-size-fits-all enforcement method that could be similarly applied in all member states. this book provides valuable information to academia, practitioners as well as policy-makers at eu and at member state level.