This book focuses on the mechanical properties and permeability of coal, and the gas flow in coal seams. Based on coal permeability models, it establishes different models for coal seam gas, from the linear flow model to the gas–solid coupling flow model. It also provides the theoretical basis for the exploitation and safe production of coal as well as coal seam gas resources. As such, it is a valuable reference for researchers, advanced students and practitioners working in mining engineering and coalbed methane engineering.