Enlargement has been a way of life for the European Union for some time now as it has sought to cope with both opportunities and challenges accompanying its increase in size from fifteen to twenty-five -- and eventually more -- member states. The enlargement that has seen eight Central and Eastern European countries, plus the two small Mediterranean islands of Cyprus and Malta, join the EU has been both momentous and unprecedented. It has been so in terms of its sheer scale, its implications for the political and economic maps of Europe, and its impact on the Union. It is with the impact of enlargement on the Union that this book is primarily concerned. The book brings together specially commissioned chapters by leading authorities to produce a comprehensive assessment of the historical and theoretical context of enlargement and the implications of enlargement for the EU's identity, governance, economics, policies, and international roles and influence.