This document has been prepared on behalf of the United Nations Environment Programme (UNEP) by the World Conservation Monitoring Centre (WCMC). Its purpose is to provide useful information on inland waters and their biodiversity to a wide audience, ranging from those interested in the state of the world environment generally, to those needing an overview of the global and regional context in order to improve planning, management and investment decisions. This report is explicitly preliminary in approach, largely because of the enormous scope of the issues involved, but by striving to be geographically comprehensive and to use existing data and expertise to best advantage, we aim to provide a firm foundation for subsequent more detailed assessment of freshwater biodiversity. Within this general context, the project has three principal objectives: -to present a global overview of freshwater biodiversity, covering notable aspects of distribution, use, status and trends: see chapters 1, 2 and 3; -to produce a preliminary global assessment of areas of special importance (hotspots) for freshwater biodiversity: see chapter 4; -to develop a framework for comparative analysis of major river basins, using indicators of biodiversity, the condition of catchment basins and pressures on water resources, in order to generate indices of importance and risk.