Fundamentals: The Tensor Structures Induced by Contact Friction -- Natural Compatibility With Mechanical Heterogeneity -- Strain Localization and Shear Banding: The Genesis of Failure Lines -- Failure Criterion: The Micromechanical Basis of Coulomb Criterion -- Coupling Between Shear Strength and Volume Changes: Generalized 3D Stress-Dilatancy Relations -- Experimental Validations -- Cyclic Compaction Under Alternate Shear Motion -- Geostatic Equilibrium: the K0 Effect -- Scale Effects in Macroscopic Behavior Due to Grain Breakage -- Practical Applications of Scale Effects to Design and Construction -- Concluding Remarks -- Appendices.