In 1978, two case studies, focusing on development problems of the Notec (Poland) and Silistra (Bulgaria) regions, were initiated at the International Institute for Applied Systems Analysis (IIASA) within the Regional Development Task. Work on these studies is being carried out by IIASA scholars in collaboration with members of Polish and Bulgarian institutions, respectively, and preliminary findings were published between 1978 and 1979 by IIASA and the Systems Research Institute of the Polish Academy of Sciences. 

Since 1978, considerable progress has been achieved. The intermediate stage of the case studies is now complete and the results are documented in these Proceedings (volumes I and II). The papers included in this publication were presented at the joint Notec-Silistra meeting, which took place at IIASA on 28 May--1 June, 1979. This meeting provided the first opportunity for the three groups participating in the investigations to compare approaches, models, and results, thus stimulating further methodological development and an extension of case-study activities. The final stage of the Notec and Silistra case studies is now underway.