this book constitutes the refereed proceedings of the third international workshop on grid computing, grid 2002, held in baltimore, md, usa in november 2002.the 22 revised full papers and 6 work-in-progress papers presented were carefully reviewed and selected from 78 submissions. the papers are organized in topical sections on applications and frameworks, optimization and performance, programming models, resource discovery and management, security and policy management, scheduling, grid infrastructure and services, and data services.