The Introduction provides an overview of the research project 'The Role and Future of National Constitutions in European and Global Governance', which was funded by a five-year grant of 1.2 million EUR, awarded by the European Research Council (ERC). The research findings are published in the present two-volume book, containing national reports from twenty-eight EU Member States, and a twenty-ninth reportfocusing on constitutional reforms related to global governancefrom Switzerland. The reports are based on the project Questionnaire. The main themes are threefold: (a) constitutional amendments with a view to EU membership; (b) constitutional adjudication at the national level regarding EU measures such as the Data Retention Directive, European Arrest Warrant and ESM Treaty; and (c) novel challenges that are increasingly highlighted in the wider context of global governance (i.e. beyond the classic international treaties that advance human rights, peace and environmental protection) in relation to democratic participation, judicial review and the rule of law. Whilst in the mainstream discourse national constitutions have typically