This text presents the leading edge in several related fields, specifically object-orientated programming, open distributed systems and formal methods for object-oriented systems. Topics discussed include: object-oriented design and programming; formal specification of distributed systems; open distributed platforms; types, interfaces and behaviour; and formalization of object-oriented methods. This volume comprises the proceedings of the International Workshop on Formal Methods for Open Object-based Distributed Systems (FMOODS '97), sponsored by the International Federation for Information Processing (IFIP) held in Canterbury, United Kingdom, in July 1997.