This text presents a unified framework for theory and practice, which is proven theoretically and by many cases from various engineering fields. There are four major aspects to the book. Firstly, it develops a formal systems approach to design (including theorems, analysis of principles of design and information theory). Secondly, methods for efficient design are rigorously derived from the theory, based on AI and optimization. Thirdly, the text covers many engineering disciplines under a unified framework, including mechanical, electrical, civil, industrial, manufacturing systems, and apparel industry. It also provides the methodology for developing the next generation computer software for advanced intelligent CAD (Computer Aided Design). Audience: The book is especially appropriate for courses in engineering (mechanical, industrial, electrical, and civil). It should be useful reference for practicing engineers interested in design and optimization, and for applied mathematicians and computer software developers engaged in smart CAD applications.