EC practice has since long felt a need for more and better-suited legal and administrative tools than the classical trias of regulation, directive and decision provide. Some new tools have emerged, such as interinstitutional agreements, commission administrative guidance, and autonomous technical standards. Regulations and directives have functionally been distinguished into legal acts of legislative and of executive value. Based on 9 studies on member states experiences with their law categories and drawing on 16 analyses of the major legal tools formally or informally used by the EC institutions the report presents a proposal for a reformed system of EC legal acts, their functions, and their institutional sources. The report was commissioned by the General Secretariat of the European Commission.