Ring-forming Polymerizations is a part of a volume that features a complete review and compilation of ring-forming polymerization reactions that result to heterocyclic ring formation. This book shows relevant growth in terms of research and commercial development in the area of polymer chemistry. This volume is comprised of four major chapters and is organized according to the specific heterocyclic ring structure resulting from ring-forming polymerizations. Each of the chapters is arranged further according to the polymer type and the different methods used in the preparation of that type, where emphasis is given to synthetic methods. This book specifically discusses the linear polymers that were intentionally made. Also, the structures presented are limited in scope considering that they are the result of the research cited in this book. However, claims that dispute a certain structure found in the research are also included to provide balance, fairness, and objectivity. Specifically, this book is a valuable resource for polymer and organic chemists. However, it can also be of great use to those scientists and researchers interested in the study of polymer chemistry of living systems.