The subject matter of this book deals with fundamental questions such as: where do industrial chemicals come from?; how are they made?; what determines which of these chemicals are produced in commercial quantities?; and what are the economic factors which affect production and pricing levels of these chemicals? These studies were done by the author using a technique he calls the "Building Block Approach". This means using a given chemical structure which is usually produced by the assembly of structural units that differ in the number of variations and the presence of important hetero atoms. The author demonstrates the usefulness of this approach in the recognition of potential choices of chemical assembly operations and that repeated applications of this approach will develop skill in recognizing industrially useful synthetic procedures.