List of Contents -- Introduction: -- Innovative Conceptual Perspectives for Adequately Modeling Complex Real Systems -- Problem Study 1 -- Realism in Hierarchical Modeling: A Fuzzy Systems Approach -- A Logical Approach to Simulation (TS - PROLOG) -- Modeling and Simulating Nets of Agencies with BORIS -- A Systems Specification Language -- An Exercise in Achieving Goals in Distributed Systems by Means of Interaction Systems -- Problem Study 2 -- Eliciting the Real Problem -- A Group Process Approach to Organizational Change -- The Problem of Model Adequacy Exemplified Using General Nets to Describe a Citizens' Services Department -- Real System Modeling: A Formal but Realistic Approach to Organizational Design -- A High Level Net Language for Stepwise Modeling Organizational Systems -- Some Mathematical Methods for Modeling the Performance of a Distributed Data Base System -- T3SD as a Modeling Methodology -- Problem Study 3 -- Quality Assurance of System Design and Model Management for Complex Problems -- Reversal Simulation with Place - Transactor Nets -- Conditions for Living Together of Social Groups -- A Balanced System of Social Groups in a New Suburb: How These Requirements Reflect on a Philosophy of Realistic Model-Building Architecture -- System for Interactive Modeling of Socio-Economic Development -- Real Structure Modeling: Towards a Valid Approach for Social Systems Analysis -- The Use of Structured Design Methodology to Improve Realism in National Economic Planning -- A Preliminary Framework for Urban Model-Building -- Authors' Index.