1 Formal Aspects of Concurrent Systems.- A Formal Basis for the Specification of Concurrent Systems.- On the Construction of Distributed Programs.- Derivation of Distributed Algorithms.- 2 Design Issues for Distributed Operating Systems.- Design of Highly Decentralised Operating Systems.- Communication Models for Distributed Computation.- New Concepts for Distributed System Structuring.- 3 Hardware Support for Distributed Computing Systems.- Distributed Computing System Architectures: Hardware.- Hardware Support for the Distributed Operating System of the Heidelberg Polyp Processor.- 4 Case Studies.- The Apollo DOMAIN Distributed File System.- The CHORUS Distributed Operating System: Some Design Issues.- The Conic Support Environment for Distributed Systems.- An Experience in Solving a Transaction Ordering Problem in a Distributed System.- Distributed Transaction Processing and The Camelot System.- Worm Programs.