Grid computing is a major research area with strong involvement from both academia and the computing industry. The common vision is that grid computing represents the culmination of truly general distributed computing across various resources in a ubiquitous, open-ended infrastructure to support a wide range of different application areas. Although significant progress has been made in the design and deployment of grids, many challenges still remain before the goal of a user-friendly, efficient, and reliable grid can be realized. Grid research issues cover many areas of computer science to address the fundamental capabilities and services that are required in a heterogeneous environment, such as adaptability, scalability, reliability and security, and to support applications as diverse as ubiquitous local services, enterprise-scale virtual organizations, and internet-scale distributed supercomputing. Cloud computing is also emerging as an alternate platform for large-scale distributed applications where resources are typically provided by a single administrative domain in a pay per-use mode. To some, cloud computing is a natural evolution of grid computing, to others, it is a complementary and perhaps competing technology. Grid and cloud research will greatly benefit from interactions with the many related areas of computer science, making Euro-Par an excellent venue to present results and discuss issues.