The key concepts that lie within the realm of natural product chemistry are considered. This includes a consideration of isolation, synthesis and biosynthesis of natural products and the importance of reductionism and complexity. Kant’s view of empiricism is mentioned. Particular examples are given from the area of bioactive natural products (medicinal chemistry), colour and flavour compounds and interactions of natural products with living systems. Themes are introduced which are subject to more detailed consideration in succeeding chapters. Particular attention is given to isolative techniques and specific examples examined (for example, the use of chromatography) and to bioactivity guided isolation. The concept of the ‘Magic Bullet’ as described by Ehrlich is discussed and its ramifications noted. Finally two important aspects of natural product chemistry—the interaction of compounds with complex biological systems and the idea of engineering pathways to optimise natural product isolation is introduced.