This book constitutes the refereed proceedings of the 6th International Conference on Intelligence in Services and Networks, IS&N '99, held in Barcelona, Spain, in April 1999. The 40 revised full papers presented were carefully reviewed and selected for inclusion in the book. There are topical sections on communications management, intelligence in brokerage and retrieval, interworking, issues in agent technology, component reuse, mobility management, service creation, multimedia services and security, mobility in TINA, distributed intelligence in networks and services, and agent support for the management of resources, networks and enterprises.