Conceptual design is considered as the most critical and important phase of design process. It is the stage where product¿s fundamental features are determined, large proportion of the life cycle cost of the product is committed, and other major decisions are made, which have significant impact on the downstream design and manufacturing processes. It is a knowledge intensive process where diverse knowledge and several years of experience are put together to design quality and cost effective products. Unfortunately, computer support systems for this phase are lagging behind compared to the currently available commercial computer aided design tools for the later stage of design. This book presents a framework of computer based computational tool known as conceptual design support tool to address these problems. The tool assists designers, mainly mechanical engineers, in performing functional modelling, concept generation, displaying the generated concepts on the morphology chart, concept combination, and concept evaluation in the early stage of design. The book also addresses design knowledge management system by using design reuse philosophy for future design.