Pharmaceutical research has become a highly rational although still developing science. In the course of a few decades, preparing plant extracts has been replaced by biophysical measurements, computer modeling of protein and drug molecules, and biotechnology. In recent years, however, ethnomedicine and tropical biodiversity are being proposed as alternative sources of badly needed or, as some believe, safer drugs.

In this chapter we bridge the communication gap between the specialist and the interested non-specialist as we describe the nature of modern pharmaceutical science. We first go back about 150 years to trace some of the concepts of modern drug discovery. Two examples from the recent literature then illustrate how chemical experience, rational methods and ‘natural products’ work together in the development of a pharmaceutical. We contrast these examples with three recent discoveries of extraordinary drugs that nature has given us. And finally we summarize the relative merits of the two approaches and briefly discuss biodiversity issues that are extremely important for pharmaceutical innovation today.

The pharmaceutical scientist thinks in terms of chemical structures. They are pieces in the gigantic puzzle that we are still assembling. For this reason we accompany our narrative with some of these pictures. Without them, ‘bridging the gap’ would be incomplete.