This book constitutes the thoroughly refereed post-proceedings of the First International Workshop on Peer-to-Peer Systems, IPTPS 2002, held in Cambridge, MA, USA, in March 2002.The 30 revised full papers presented together with an introductory survey article were carefully selected and improved during two rounds of reviewing and revision. The book is a unique state-of-the-art survey on the emerging field of peer-to-peer computing. The papers are organized in topical sections on structure overlay routing protocols, deployed peer-to-peer systems, anonymous overlays, applications, evaluation, searching and indexing, and data management.