Object-based Distributed Computing is being established as the most pertinent basis for the support of large, heterogeneous computing and telecommunications systems. The advent of Open Object-based Distributed Systems (OODS) brings new challenges and opportunities for the use and development of formal methods. Formal Methods for Open Object-based Distributed Systems presents the latest research in several related fields, and the exchange of ideas and experiences in a number of topics including: formal models for object-based distributed computing; semantics of object-based distributed systems and programming languages; formal techniques in object-based and object oriented specification, analysis and design; refinement and transformation of specifications; multiple viewpoint modeling and consistency between different models; formal techniques in distributed systems verification and testing; types, service types and subtyping; specification, verification and testing of quality of service constraints and formal methods and the object life cycle. It contains the selected proceedings of the International Workshop on Formal Methods for Open Object-based Distributed Systems, sponsored by the International Federation for Information Processing, and based in Paris, France, in March 1996.