Advancement of science and technology and its impact on real life applications is more and more strictly related to the progress and availability of high performance parallel computer systems and grids, the novel networked infrastructures aimed to organize and optimize the use of a huge amount of distributed data processing and computing resources. This book collects in four chapters single monographs related to the fundamental advances in parallel computer systems and their future developments from different points of view (from computer scientists, computer manufacturers, end users) and related to the establishment and evolution of grids fundamentals, implementation and deployment.The aim is to cover different points of view in the field by actors playing different roles, to orchestrate and correlate their interconnection and coherence, and - above all - to show behaviors, impacts, performances of architectures, systems, services and organizations in action. Accordingly, the expected audience would be broad, mainly made up by computer scientists, Ph.D. students, post-doc researchers, specialists of computing and data centers, computer engineers and architects, project leaders, information system planners and professional technologists.