This book constitutes the thoroughly refereed joint post-proceedings of two workshops on web engineering and peer-to-peer computing held in conjunction with NETWORKING 2002 in Pisa, Italy, in May 2002. The 31 revised full papers presented were carefully selected during two rounds of reviewing and improvement. They are organized in topical sections, models and characterization of web traffic, caching infrastructure and content delivery networks, building web-based systems, web server performance analysis, routing and discovery in peer-to-peer networks, applications, programming models for peer-to-peer systems, and security in peer-to-peer computing.