This title covers the fundamental properties of rock joints, the methods of laboratory testing of rock joints, and shear strength assessment under different loading conditions. The use of the Constant Normal Stiffness method for analyzing the behaviour of rock joints and representing the laboratory response in terms of stress paths are discussed in depth. A shear strength model developed by the authors using a mathematical approach is also highlighted with simplified practical applications. This work is intended as a reference text for students and practitioners in mining and rock engineering.