As stated in “About This Book,” the author isn’t going to take the usual approach to the subject of chemistry. Because virtually all explanations of chemical reactions are based on our current model of atoms and molecules, the first thing to do here is to help you understand why we believe that atoms and molecules look and act the way they do. That’s not a trivial issue, because despite the impression you might have gotten from textbooks, no one has ever seen an atom in the sense that you can see this page in front of you. What we have are observations and experiments that lead us to formulate models of atoms. This free selection includes the Table of Contents, Preface, About This Book section, a Safety Note, and the Glossary.