An important recent idea to facilitate knowledge sharing is to provide libraries of reusable components (models, ontologies) to end users. However, when libraries become large, finding the right library components is a knowledge demanding task in itself. Our suggestion therefore is that methods will be needed that help the user to gradually construct such knowledge.

This paper argues that the reuse of domain knowledge must be complemented by the reuse of problem-solving methods. Problem-solving methods (PSMs) provide a means to structure search, and can provide tractable solutions to reasoning with a very large knowledge base. We show that PSMs can be used in a way which complements large-scale representation techniques, and optimisations such as those for taxonornie reasoning found in Cyc. Our approach illustrates the advantages of task-oriented knowledge modelling and we demonstrate that the resulting ontologies have both task-dependent and task-independent elements. Further, we show how the task ontology can be organised into conceptual levels to reflect knowledge typing principles. 1