The first chapter of this book was entitled "The View from a Distant Universe." In the chapters that followed, we moved in our mind's eye from galaxies and stars down to atoms and subatomic particles. We saw how atoms are synthesized at very high temperatures in stellar interiors, and how at much lower temperatures these atoms associate into molecules and condense into liquids and solids. We saw how atoms are constructed from electrons, neutrons and protons, and the way in which the structure of atoms brings about a broad range of chemical properties and behaviour, culminating in the periodic table. Especially in the preceding seven chapters we have seen how these atoms and molecules react with one another, by breaking chemical bonds and forming new ones, and absorbing or releasing energy.

Nowhere in this chemical landscape have we yet seen ourselves or the most remarkable of all chemical phenomena, life. Life is a special kind of chemical system that arose in our corner of the universe (and probably elsewhere, though we have no evidence yet) in a restricted size and temperature range, using a relatively small number of the possible kinds of atoms. "Man is the measure of the universe" is an often quoted epigram. In reality the universe stretches for many orders of magnitude to either side of the range that man can comprehend easily. One of the purposes of this chapter is to place man and other living organisms in their proper setting.