This book is written to make this appreciation easier. It is not a text-book of chemistry, and it does not attempt to supplant any of the standard treatises. Rather it is to supplement them, to show the pattern within which much of the contents of these
treatises fits; to exhibit the fundamental reasons why molecules are what they are and how the theoretician looks at his problems as they arise. Practically no mathematics is needed for this purpose, since almost everything necessary can be put in pictorial terms. Contrary to what is sometimes supposed, the theoretical chemist is not a mathematician
thinking mathematically, but a chemist, thinking chemically. That is why almost everything in this book should be understandable to a chemist with no mathematical attainments.