These Proceedings report the scientific results of an International Workshop on Methodology and Software for Interactive Decision Support organized jointly by the System and Decision Sciences Program of the International Institute for Applied Sys tems Analysis (nASA, located in Laxenburg, Austria) and The National Committee for Applied Systems Analysis and Management in Bulgaria. Several other Bulgarian institutions sponsored the Workshop - The Committee for Science to the Council of Ministers, The State Committee for Research and Technology and The Bulgarian In dustrial Association. The workshop was held in Albena, on the Black Sea coast. More than 80 scientists from 15 countries attended the workshop; 50 lectures were presented and 17 computer demonstration sessions took place. This Workshop is one of a series of meetings organized by nASA with the collaboration of scientific institutions from the National Member Organization countries. The previous meetings took place in Austria (1983), Hungary (1984) and the German Democratic Republic (1985). All proceedings of these meetings have been published by Springer Verlag in the series Lecture Notes in Economics and Mathematical Systems."

It is not easy to summarize -even in a volume -the results of a scientific study con ducted by circa 30 researchers, in four different research institutions, though cooperating between them and jointly with the International Institute for Applied Systems Analysis, but working part-time, sponsored not only by IIASA's national currency funds, but also by several other research grants in Poland. The aims of this cooperative study were de fined broadly by its title Theory, Software and Testing Examples for Decision Support Systems. The focusing theme was the methodology of decision analysis and support related to the principle of reference point optimization (developed by the editors of this volume and called also variously: aspiration-led decision support, quasi-satisfying framework of rationality, DIDAS methodology etc. ). This focusing theme motivated extensive theoretical research - from basic methodological issues of decision analysis, through various results in mathematical programming (in the fields of large scale and stochastic optimization, nondifferentiable optimization, cooperative game theory) mo tivated and needed because of this theme, through methodological issues related to software development to issues resulting from testing and applications. We could not include in this volume all papers -theoretical, methodological, appiied, software manu als and documentation -written during this cooperative study."