The Agencies of the European Union form an integral part of European Administrative Law. The first scientific part analyses the characeristics of agencies and proposes a defintion of agencies. Based on these results, the variety of agencies is classified. The second scientific part adresses the appropriate legal basis and further requirements for the establishment of agencies and the delegation of powers to agencies. The analysis is based on the relevant jurisdiction of the European Court of Justice. In the last scientific part the results of the previous chapters are applied to the European Insurance and Occupational Pensions Authority.