The book provides a guide to rock engineers and engineering geologists as to how to perform laboratory tests and how to use the existing data for solving practical rock engineering design and operating problems. Knowledge of the behavior of rocks under general triaxial compression is also of crucial importance in the fields of structural geology and tectonophysics as the effect of the intermediate and the minimum principal stresses may be a decisive factor in the mode of deformation and processes of gross-fracturing, faulting and earthquakes.