Book excerpt: This book constitutes the refereed proceedings of the First International Workshop on Multimedia Interactive Protocols and Systems, MIPS 2003, held in Napoli, Italy in November 2003. MIPS continues the form IDMS/PROMS Workshop series. The 34 revised full papers presented were carefully reviewed and selected from more than 130 submissions. The papers are organized in topical sections on wireless multimedia systems, communication protocols for multimedia, scheduling, caching, quality of service architectures, novel communication services, middleware, infrastructure, IP telephony, multimedia applications, and encoding.