The papers in this volume were presented at the Second Annual Work- shop on Active Middleware Services and were selected for inclusion here by the Editors. The AMS workshop was organized with support from both the National Science Foundation and the CAT center at the Uni- versity of Arizona, and was held in Pittsburgh, Pennsylvania, on August 1, 2000, in conjunction with the 9th IEEE International Symposium on High Performance Distributed Computing (HPDC-9). The explosive growth of Internet-based applications and the prolifer- ation of networking technologies has been transforming most areas...