This chapter points out that to cope with the rapidly expanding open world where there are no oundaries and where changes are frequent and extensive and requirements are too much iversified, we need to step out of the traditional engineering framework of Max Weber’s weckrationalitaet or instrumental rationality or in another word, the world of explicit knowledge and move toward the world of Wertrationalitaet or value rationality. Values are evaluated based onperformance in traditional engineering. But this performance has been none other than functions. So, value in the traditional engineering is very objective. And it is discussed in the ramework of theoretical rationality. But to change our minds from instrumental or means-ends ationality to value rationality, we should look at value on a personal basis, i.e., value tomorrow will be very much subjective and personal. And products and services will be developed to generate such personal values. The basic framework of our engineering tomorrow will be value-oriented ationality.