NextGrid project (IP): The Next Generation Grid (2004-2008). Sixth Research Framework Programme (FP6). Contract No. 511563. Funded by the Commission of European Communities Information Society and Media Directorate-General, the project addresses the Grid Based Systems for Complex Problem Solving activity within the IST Work programme. It specifically focuses on the second strategic objective of this activity and is designed to overcome present architectural and design limitations hampering the use and wider deployment of computing and knowledge Grids and to enrich its capabilities by including new functionalities required for complex problem solving.