The European Security Forum brings together senior officials and experts from EU and Euro-Atlantic Partnership countries, including the United States and Russia, to discuss security issues of strategic importance to Europe. Now in its sixth year of operation, the Forum is jointly directed by the Centre for European Policy Studies (CEPS), the Geneva Centre for the Democratic Control of Armed Forces (DCAF), and the International Institute for Strategic Studies (IISS) in London. The ambition of this fourth annual volume of Readings in European Security is to serve as a prism through which the EU's external relations and security can be assessed, with contributions from its American and Russian partners. The book contains the complete set of working papers presented and discussed from January through December 2006. During this period, international experts tackled highly topical strategic issues ranging from the security of energy supplies in Europe to Ukraine's strategic security to Islamic extremism in Europe to the strategic implications of the failed EU Constitutional Treaty.