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.