The main objective of this publication is establishing an understanding of the process of European integration and hence the current European Union that has resulted from this process. As this is a complicated development that includes many different areas, this book will focus on the main fields in which the integration has been settled; politics, economy, law, and social aspects. Thus, a comprehensive approach to all these fields will provide both general and professional readers with sufficient knowledge to understand the process and form their own opinion about it. Each chapter has been developed independently, and hence can be read autonomously in order to understand a specific topic, policy, or problem in the European Union. Reading of the full book will provide a wide perspective of the process, as the chapters are connected; forming different groups based on similar themes, the combination of these wider groups providing the general approach to the whole process of European integration.