Declarative programming languages are based on sound mathematical foundations which means that they offer many advantages for software development. These advantages include their powerful descriptive capabilities, the availability of program analysis techniques and the potential for parallel execution. This volume contains the proceedings of a seminar and workshop organised by the Esprit Basic Research Action Phoenix in collaboration with the Esprit Basic Research Action Integration. Both these groups have been closely involved in investigating the foundations of declarative programming and the integration of various language paradigms, as well as the developing aspects of related technology. The main aim of the seminar and workshop was to provide a forum for the results of this work, together with contributions from other researchers in the same field. These papers cover a variety of important technical areas such as foundations and languages, program transformation and analysis, integrated approaches, implementation techniques, abstract machines and programming methodology. The resulting volume provides an in-depth picture of current research into declarative programming. It will be of special interest to researchers in programming languages and methodology, students of artificial intelligence and anyone involved in industrial research and development.