This book provides an in-depth review of refiner-based mechanical pulping technology, specifically thermomechanical pulp (TMP) technology. The authors offer a readable and straightforward discussion of the technology, energy requirements, pulp quality characteristics, and morphological aspects of the thermomechanical pulping process. It is intended primarily to provide a useful introduction to young process engineers working in mechanical pulp mills in the early stages of their careers but with sufficient detail to provide the reader with a broader understanding of the overall process. University undergraduates as well as postgraduate students may also find this book to be a reliable resource. In addition, technologists and technical sales staff employed by equipment and chemical suppliers supporting the mechanical pulping industry will gain an improved understanding of the technology. This book offers a detailed overview of issues related to the market demand and production of high-yield market pulp, including wood composition and fibre morphology, the refining, screening and bleaching processes, and energy-saving approaches that reduce energy reliance without compromising quality. The authors provide a sound foundation for successful TMP plant operation as well as a reasonable starting point for any investigation into pulp-quality issues that may arise due to changes in chip supply or TMP plant operating parameters.