: The need for analysis and modeling of knowledge has been espoused by many researchers as a prerequisite to building knowledge based systems (KBS). This approach has done little to alleviate the knowledge acquisition (KA) bottleneck or the maintenance problems associated with large KBS. For actual KA and maintenance we prefer to use a technique, known as ripple down rules (RDR) that is simple, yet reliable, and later see what models can be produced from the knowledge for the purpose of reuse. Tools based on Formal Concept Analysis have been added to RDR to uncover and explore the underlying conceptual structures. 1 Models and their Role in Knowledge Acquisition Since Newell's [21] paper on "The Knowledge Level" there has been increasing awareness and acceptance of the need to model knowledge at a level above its symbolic representation. This notion was further explored by Clancey [3] who used task and problem solving methods analysis to divide problems into "heuris...