1 Introduction.- 2 Information Systems Development.- I Foundations.- 3 Basic Notions of System Specification and Modeling Approaches.- 4 Semantic Concepts.- Language Definition.- 5 Basic Constructs in Troll.- 6 Template, Object, and Class Specifications.- 7 Relating Specifications.- 8 Specification of Systems.- III Discussion.- 9 Related Approaches.- 10 Discussion and Outlook.