The existence of the computer coupled with the rapid development of analytical engineering techniques has made it possible to design complex systems which are different and better, and to do so in a manner that is more efficient. Examples from the aircraft industry include hypersonic airplanes in which the fuel serves as a coolant to heat sensitive frame components, and the frame serves as part of the engine. Thus, design changes to any single part have cascading effects on the entire Bystem. This leads to extreme complexity in the design process and requires extensive computational resources and sophisticated computer techniques to proceed in a rational manner. For example, large scale systems theory and multi-level optimization are some of the approaches applicable to this class of design problems. Similarly, in advanced automotive systems, new ideas, which appear at the outset to be and/or affect only subsystems, (e.g., energy storage devices, active suspension systems, etc.) cannot even be considered using other than a vehicle system design, and they also may dramatically alter the system operation. This is particularly important since automobile users are a relatively heterogeneous, unskilled group. A systems approach, which integrates all aspects of product definition, design, manufacturing and use, is required to solve the dilemma. The systems approach requires the development of top-down design tools and techniques for mission definition, functional analysis, concept development and design. All salient issues must be considered from the outset and throughout, including manufacturability, reliability, serviceability, etc. And if a systems approach is used it becomes a mechanism and stimulus for the integration and resultant synergism of previously separated technical issues and disciplines.