This book constitutes the refereed proceedings of the IFIP/ACM International Conference on Distributed Systems Platforms and Open Distributed Processing, Middleware 2000, held in New York, NY, USA, in April 2000. The 21 revised full papers presented were carefully selected from a total of 70 submissions. The book offers an excellent state-of-the-art report on research in the design, implementation, deployment, and evaluation of distributed systems platforms and architectures for future networked environments. The papers are organized in sections on caching, indirection, reflection, messaging, quality of service, transactions and workflow, and composition.