In 2003, UN Secretary-General Annan appealed to the international community to reform the United Nations system. A high-level panel was established to elaborate proposals, which shall be presented to the General Assembly in 2005. In this context, French President Chirac called for establishing a new United Nations Environment Organization (UNEO), to evolve from the UN Environment Programme (UNEP). France set up a working group on this issue, consisting of 26 countries and the EU Commission, and including both supporters and critics of the initiative. The aim is to work out a concept for a UNEO by 2005. In parallel, continued efforts are made to strengthen UNEP. Reform aims at enhancing its financial basis, expanding the membership of the UNEP Governing Council to all UN Member States and increasing the activities in the fields of science and capacity building. The present volume, which consists of a series of contributions by internationally renounced authors, analyzes gaps and weaknesses of the present system of global environmental governance, and highlights the various aspects, challenges and necessities, of a political and scientific nature alike, of both reforming UNEP and creating a new environment organization in context of the major United Nations reform effort.