The explosive growth of Internet-based applications and the proliferation of networking technologies have transformed not only the computer science and engineering fields but also has affected the areas of computational science and commercial Internet applications. This has provided researchers with an opportunity to explore new Internet-oriented software technologies designed to expand research and application opportunities in multimedia, commerce, and the scientific and high-performance computing applications community. Two emerging technologies - agents and active networks - provide increased programmability to bring new services to Internet-based applications. The chapters in this volume are based on presentations at the Second Annual Workshop on Active Middleware Services. The volume draws on research results in active networks, mobile and intelligent agents, software tools for high-performance distributed computing, network operating systems, and application programming models and environments. The text should be appropriate for engineers and researchers in the areas of network centric computing and distributed information systems, as well as for application and tool developers and users of information systems.