Preface --Introduction --State aid decisions and open formal investigations concerning the tax ruling practices of member states --Arm's length principle --Recovery, legitimate expectations and legal certainty --EU competences --International practices and the OECD --The way forward.

An harmonized EU corporate income tax - i.e. a traditional tax aimed at raising resources for a common fiscal policy - is not attainable in the short term: the Treaty unanimity rule is an obstacle and the priority is constituted by the (unresolved) EU fiscal architecture. However the...