Rocks are complex materials and issues related to failure and strength and their relations to the modes of deformation and degradation must be addressed as a multiphysics and multiscale problem involving several different spatial and temporal scales. The recent computational capabilities of contemporary engineering and experimental facilities including multiphysical couplings permit to go beyond commonly used tools of engineering practice. It is not possible in a single chapter to cover the large variety of recent advances in rock mechanics that have been prompted by a wide range of applications to engineering and geophysics in relation with energy production, underground storage, earthquake nucleation etc. The objective of the chapter is therefore to present a review of recent research on understanding and modelling of failure mechanisms including the effect of pore pressure, temperature, chemical reactions and microstructure in relation to strain localization and stability analysis.