The engineering (building) of chemically synthesized drugs based on knowledge of receptor modeling and drug/target interaction with the aid of supercomputers/interactive graphics/etc); the educated, creative design of the three-dimensional structure of a drug atom by atom, that is, “from the ground up.” This approach represents a major advance over the prior practice of first synthesizing large numbers of compounds (or finding them in nature), followed by thousands of tedious screenings to test for efficacy against a given disease. The approach of rational drug design has, however, not yet been perfected and optimized due, in part, to gaps in our knowledge of drug/receptor interaction and to gaps in our knowledge in general.