This report constitutes the third iteration of a comprehensive assessment of European defense trends undertaken by the CSIS Defense-Industrial Initiatives Group. The report analyzes the demand side (topline and functional defense spending categories) for 37 European countries, the supply side (the European defense, security, and space industrial base), and the regulatory environment (at the European level) governing defense, between 2001 and 2011. This iteration incorporates newly available data and adds new layers of analysis to create a more thorough assessment of the European defense market. In addition, it presents an analysis of potential future defense spending scenarios in Europe, based on current trends, and offers option sets for relevant stakeholders—national governments, the European Union, and the European defense and security industry—on how to respond more effectively to the key challenges in the European defense market.