Book excerpt: This book considers the raw materials used to build the polyurethane polymeric architecture. It covers the chemistry and technology of oligo-polyol fabrication, the characteristics of the various oligo-polyol families and the effects of the oligo-polyol structure on the properties of the resulting polyurethane. It presents the details of oligo-polyol synthesis, and explains the chemical and physico-chemical subtleties of oligo-polyol fabrication. This book will be of interest to all specialists working with polyols for the manufacture of polyurethanes and to all researchers that would like to know more about polyol chemistry.