Expert system technology has produced systems that perform heuristic classification. These systems solve problems of a type determined by the knowledge engineer and the expert at system design time. A "true consultant" on the contrary, applies domain knowledge to solve a problem not previously seen. For example, a graphic design consultant must accept the statement of almost any problem from a client and turn it into a visual design. This thesis reports the successful construction of the first such true consultant for a well-understood domain: the visual design task of chart construction. The system leads a client in a dialogue to define a problem in the client's terms and then maps the problem representation into a knowledge base for constructing charts. Extensions of the technology reported in this thesis may aid the creation of a new class of expert systems. / Master of Science