With the focus on the power of theoretical concepts to enable the creation of new technologies, separation technology is discussed in terms of "intellectual tools" derived from ideas in diffusion accompanied by reaction and from "pinch point" techniques. Ideas nr-e the intellectual tools shaping the changing world (we live not in the information age, but in the intellectual age). Developments in distillation equipment during the last 20 years reveal the importance of business drivers for stimulating change, and why the 1980s was the decade of structured packing and the 1990s of high throughout trays. Because of out inadequate understanding of phase equilibrium (no molecular theory of liquids) and of two-phase flow (except for when one phase is very dilute), process and equipment design is still essentially empirical. In conclusion it is noted that more might ha none to encourage the development of young intellectual tool-makers. Research in this field might help speed rip technical innovation.