A systematic approach is employed to elucidate the interrelationships among macroeconomic entities such as science, engineering, technology, industry and national economy. Specifically, a conceptual, sequential method has been developed to clearly identify the essential ingredients needed for each macroeconomic entity starting from science to transform to the next one, and all the way to the national economy where the production of added-value is of overriding importance. The results thus obtained can then be utilized for macroeconomists to readily apply the engineering theory and knowledge to various macroeconomics situations, while engineers can likewise utilize the results on top of the microeconomic knowledge already prevalent in many engineering fields in getting better grasp of the seemingly difficult nation’s macroeconomic picture. Other peripheral concepts and issues such as the evolutionary development of industry, the perspectives of the 21st century civilization, an analogy between macroeconomics and chemical engineering, and national policies for each macroeconomic entity are also presented in this study.