The present volume is the third in a series of VDM Symposia Proceedings. VDM, the Vienna Development Method, is a formal method for software engineering, Z refers to Zermelo, a mathematician whose name is associated with set theory. Many computing science, programming and software engineering proceedings are published regularly. The ones by VDM Europe have the distinguished mark that they are concerned with bringing real theory to apply to real programming. In Europe, there is very much interest in methodology, semantics and techniques, that is, in understanding how we build and what it is that we are building. The papers of these proceedings basically fall into four major groups: Applications, Methodology, Formalisations, and Foundations. The Methodology group has been further subdivided into five areas: Specification Methodology, Design Methodology, Modularity, Object Orientedness, and Processes, Concurrency and Distributed Systems.