Book excerpt: This book constitutes the thoroughly refereed post-proceedings of the IST/FET International Workshop on Global Computing, GC 2004, held in Rovereto, Italy in March 2004. The 18 revised full papers presented were carefully selected during two rounds of reviewing and improvement from numerous submissions. Among the topics covered are programming environments, dynamic reconfiguration, resource guarantees, peer-to-peer networks, analysis of systems and resources, resource sharing, and security, as well as foundational calculi for mobility.