How can we approach the complex United Nations system, a ‘family’ of principal organs, subsidiary organs and specialized agencies? Where do we get summarizing information on the large number of reform concepts developed and implemented since the late 1990s, in particular in connection with the UN World Summit 2005? The present book provides orientation and information: It is the second updated English edition of the German “Lexikon der Vereinten Nationen”. The book provides in addition to concise and comprehensive information on the UN system insight into recent UN developments and reform efforts in the face of global opportunities and challenges, such as the Millennium Summit 2000 and World Summit 2005, and the establishment of important new UN organs, the Human Rights Council and the Peacebuilding Commission, in 2006. The contributing authors are academic scholars of international law, economics and political sciences; active and former diplomats and UN officials; journalists and members of non-governmental organizations (NGOs), and offer a variety of interesting perspectives. The entries are provided with bibliographies and with Internet addresses for further information and are supplemented in the annex by an informative text on the UN document numbering system and by a list of information facilities concerning the UN.