This text addresses formal description techniques (FDTs) applicable to distributed systems and communication protocols. It aims to present the state of the art in theory, application, tools an industrialization of FDTs. Among the important features presented are FDT-based system and protocol engineering, FDT application to distributed systems, protocol engineeering, practical experience and case studies. This text contains the proceedings of the Joint International Conference on Formal Description Techniques for Distributed Systems and Communication Protocols and Protocol Specification, Testing, and Verification, which was sponsored by the International Federation for Information Processing (IFIP) and was held in Beijing, China, in October 1999. This volume is suitable as a secondary text for a graduate level course on Distributed Systems or Communications and as a reference for researchers and industry practitioners.