The primary objective of this research is to develop a visual design process for gear trains with multiple stages of reduction and varying configurational architectures. One of the main challenges in the design of such gear trains is in the sizing of the individual gears such that high levels of performance are obtained in spite of constraints due to different gear configurations. Formal design procedures that successfully meet this challenge are developed. A key contribution of this research is the utilization of these design procedures to create sets of three-dimensional design maps. The design procedures help a designer manage more than 20 design parameters in designing for a broad range of gear train requirements (Rated torque capacity, Volume, Weight, Inertia, Responsiveness, Torque Density etc.) while accounting for assembly constraints. Each set of design maps corresponds to a given set of design parameters, some of which are held fixed and some of which are put in the hands of the designer. The latter set of design parameters are termed in this research as design knobs. They can be ‘tuned’ by a designer in order to generate new sets of design maps. The idea is that a designer, using the design information conveyed to him/her graphically through a given set of design maps, is able to then tune the design knobs to generate an updated set of design maps which reflect design solutions that are more desirable in terms of the application requirements. By adjusting the design knobs and looking at updated design maps, a designer is able to quickly assess the effect of his/her design decisions. The end result is that a single designer is empowered with the ability to quickly arrive at a preliminary design of a gear train that satisfies the design requirements. This preliminary design would be a good starting point for more detailed design development. / text