Grid computing pioneering days are over, grid technology has matured enough to enable the realization of workable and commercial infrastructures, platforms and tools, ready to be used in production environments ranging from scientific to commercial application domains. Technology research is nevertheless still undergoing a dramatic development, involving major advances in areas such as resource management, mapping, scheduling, fault tolerance, I/O, visualization, performance analysis, programming languages and environments, resource discovery and semantic aspects. This book aims at providing a comprehensive description of most recent research achievements in grid technology, in-depth witnesses of a number of production applications of grid technology to various application domains, and of some of the most important large scale projects, directly from the leading researchers and technology managers involved. This book is intended for researchers and graduate students in computer science and engineering, and for industry technology providers, with particular interests in parallel, distributed computing and grid technology, as well as for users of grid technology, in particular researchers and technical managers in basically all areas of science, engineering and economy, both from academia, research centers and industry. The book is composed of 10 sections, and 34 chapters. For guidance to readers, in the following we will describe each section and outline the main contributions of each chapter, so that reader can better plan their perusal of the material.