The beginning of the twenty-first century will witness an unprecedented expansion of the European Union, with ten new members joining in 2004 and more seeking to follow. Compared to past expansions, the current and forthcoming enlargements possess a number of characteristics. Of these, it is noticeable that a majority of new member countries are small. In addition, the economic, political and historical backgrounds of new small member states are very different from those of the current EU membership. In this context, there is a conventional wisdom that the accession of a large number of new small member states has the potential to create challenges to the future development of the enlarged EU. These challenges will be manifested in the decision-making process of the EU, the implementation of a wide range of its policies, and the governance of its institutions. However, this book will attempt to argue that this conventional view may not necessarily be the case.