It is well recognized everywhere that management of sludge derived from wastewater treatment is one of the most critical environmental issues, due to the very fast increase in sludge production as a result of sewerage extension, new installations and upgrading of existing facilities. Within this general picture, sludge is produced under different technical, economic and social contexts, thus requiring different approaches. This report is intended to give an overview of the sludge field in different parts of the world by summarising: current wastewater and sludge treatment provision; current and anticipated legislation; current research horizons; anticipated evolution of management approaches; and prospects for application of innovative and / or simple technologies. The report has been prepared for the Water21 Market Briefing Series in collaboration with the International Water Association's Specialist Group on Sludge Management. It is based on short contributions from: Western Europe; Eastern Europe; North America; Latin America and the Caribbean; East Asia; South Asia and China; Africa; and Australasia. These are accompanied by an introduction and overview section.