Input-output modeling has, through the years, provided a consistent and unifying focus for IIASA's economic research. Scientists working in the Institute, first in the economic modeling task of the System and Decision Sciences area and later within the Economic Structural Change project, have cooperated extensively with colleagues throughout the world in advancing and contributing to input-output work. Perhaps the most notable aspect of these efforts has been the joint work with the INFORUM Project to develop linked systems of national models. Experience gained from the INFORUM-IIASA studies has been of great benefit to other members of the I/O community, but this is by no means the end of the story. Contributors not connected with INFORUM have also brought their own very valuable insights and knowledge to bear on the subject, and input-output modeling has moved progressively away from being a purely academic specialization. A number of the methods developed have direct application to economic analysis and policy formulation, and I/O techniques have achieved widespread use in both governmental and commercial environments. This volume presents the results of the fifth in a series of meetings organized by IIASA to promote methodological advances in the subject and to draw on a pool of I/O expertise so as to further the aims of the Institute's in-house economic research.