The kingdom is not an amorphous jumble of regions, but a closely organized state in which the character of one region is close to that of its neighbo… - Peter Atkins

Chemistry is the science of matter and the changes it can undergo. The world of chemistry therefore embraces everything material around us—the stones we stand on, the food we eat, the flesh we are made of, and the silicon we build into computers. There is nothing material beyond the reach of chemistry, be it living or dead, vegetable or mineral, on Earth or in a distant star.

I have presented the periodic table as a kind of travel guide to an imaginary country, of which the elements are the various regions. This kingdom has a geography: the elements lie in particular juxtaposition to one another, and they are used to produce goods, much as a prairie produces wheat and a lake produces fish. It also has a history. Indeed, it has three kinds of history: the elements were discovered much as the lands of the world were discovered; the kingdom was mapped, just as the world was mapped, and the relative positions of the elements came to take on a great significance; and the elements have their own cosmic history, which can be traced back to the stars.

It was a great achievement of the early chemists — with the crude experimental techniques available also with the ever-astonishing power of human reason (as potent then as now) — to discover this reduction of the world to its components, the chemical elements. Such reduction does not destroy its charm but adds understanding to sensation, and this understanding only deepens our delight.