This book provides a forum for researchers in scalable computing to publish extended-length articles on significant new developments. An article may present comprehensive results from a major project, review recent work in a sub-domain, or expound new ideas in a detailed, tutorial fashion, at a length which most journals and conference proceedings cannot accommodate.The five articles in this book give an excellent illustration of the different types of material requiring such extensive treatment, and should serve well to encourage future authors with similar ideas to consider publishing in the Series on Scalable Computing.