The Assistance Manager, one of the tools of the Simulation Model Development Environment (SMDE), is required to provide assistance to a user during the process of model development. This thesis describes the research effort to prototype the SMDE Assistance Manager. Requirements are set forth and a design is established for the Assistance Manager prototype. The implementation is described, and the Assistance Manager is shown to provide a highly flexible interface between the user and the database of assistance information. Assessment criteria are established, and the prototype is evaluated. Results of the evaluation indicate that the Assistance Manager incorporates the characteristics considered desirable in online assistance systems, and serves as a basis for future enhancement and development. / Master of Science