Symposium Opening Addresses.- Welcoming Address.- Welcoming Address.- Welcoming Address.- 1. User-System Interfaces: Key Issues.- Softening Up Hard Science: Reply to Newell and Card.- Design and Evaluation of User-System Interfaces or of User-Task Interaction: A Discussion of Interface Design Approach in Different Domains for Application of Modern Information Technology.- Concurrent Computer and Human Information Processing.- On Meaningful Menus for Measurement: Disentangling Evaluative Issues in System Design.- Issues and Red Herrings in Evaluating Natural Language Interfaces.- 2. User-System Interface Analysis.- Criteria and Techniques for the Objective Measurement of Human-Computer Performance.- Human-To-Machine Interaction in Natural Language: Empirical Results of Field Studies with an English and a German Interface.- Applying Operations Research Models to the Study of Complex Man-Machine Interfaces.- 3. User-System Interface Evaluation.- Adaptive User Interfaces for Information Systems: An Evaluation.- DIADES: A Design Tool for Interactive Programs with Provisions to Assess Design Decisions About the Man-Machine Interface.- An Outline of Techniques for Evaluating the Human-Computer Interface.- Software Complexity Assessment and Human-Machine Interface Evaluation.- 4. User-System Interaction.- A Comparison of the Usability of SQL vs a Menu-Driven Interface.- Use of Query Language Boolean Operators by Professionals.- Man-Computer Interaction in Computer-Aided System Analysis and Design: Application of PSL/PSA.- Layout and Highlighting in On-Line Information.- 5. Information System Design and Development.- Performance Measurement and Tuning of Interactive Information Systems.- A Method for Designing Tools for Information Retrieval From Documents.- Implementing Modifications of Information Systems While Using Them: An Intentionally Intervening Approach.- The Semantic Model in Information Retrieval.- 6. Software Engineering.- Counting Leaves An Evaluation of Ada, lĂ^