The aim of CoreGRID is to strengthen and advance scientific and technological excellence in the area of Grid and Peer-to-Peer technologies in order to overcome the current fragmentation and duplication of effort in this area. To achieve this objective, the workshop brought together a critical mass of well-established researchers (including 145 permanent researchers and 171 PhD students) from a number of institutions which have all constructed an ambitious joint program of activities. Priority in the workshop was given to work conducted in collaboration between partners from different research institutions and to promising research proposals that could foster such collaboration in the future.  This book is the fourth volume of the CoreGRID series.

The topics in this volume include: - Knowledge and Data Management, - Programming Models, - System Architecture, - Grid Information, Resource and Workflow Monitoring Services, - Resource Management and Scheduling, - Systems, Tools and Environments, -Trust and Security Issues on the Grid.