This book constitutes the refereed proceedings of the 4th International COST 237 Workshop, held in Lisboa, Portugal, in December 1997 of the European COST Programme on Multimedia Telecommunication Services. The 12 revised full papers presented were selected from 24 submissions. The topics covered include multimedia presentation, QoS Control, electronic commerce, CORBA and DCE, real-time multimedia, multimedia conferenceing, multicast networking, heterogeneous communications environments, and others.