In one of his letters, Saint Paul the apostle uses smell as a metaphor for the gospel, but in this, he actually describes truths about perfume and about the sense of smell. Research over the last few decades has shown that Paul's observation regarding the latter conveys a deeper truth about odour perception than he would have been able to appreciate. In fact, the understanding of perception that we now have gives insight into the very nature of human individuality. This chapter also helps to set the scene for appreciation of the later chapters concerning the use of perfume.