Conceptual modeling of complex information systems requires the use of a formal design approach covering both static and dynamic aspects of the system and the modeled Universe of Discourse. A language for conceptual modeling is regarded as a means to write contracts between customers and system designers. Thus on the one hand a certain degree of \em readability of specifications is necessary for the domain specialist and on the other hand formality is necessary to derive information for further design, implementation, and prototyping issues. In this extended abstract we present the modeling language \sc Troll that provides a notation close to object oriented programming languages but also incorporates declarative features for high level design documents.