This paper concerns a project using the case method of instruction to develop an Intelligent Tutoring System (ITS) for military decision-making skills. Our technical objective is actually the authoring shell that lets domain experts and educators enter new cases into a library and then use stored cases in creating lessons that foster analogical encoding in students, a mental process shown empirically to improved acquisition, retention, and transfer of domain knowledge. We have adopted a collaborative view of human-machine interaction in order to construct an integrated cognitive system in which analogical reasoning by the machine supplements and enhances analogical reasoning by the human. In this instance the supported forms of human reasoning are analogical encoding by students at instruction delivery time and analogical recall by experts at authoring time. The focus of this paper is the design and implementation of the case-authoring component of the authoring shell that assists domain experts in creating new cases and integrating them into the case library.