Book excerpt: · Proceedings of 12th International Workshop on Bifurcation and Degradation in Geomechanics (IWBDG2022) held on 28 November - 1 December 2022 at the University of Western Australia, in Perth, Australia. The book concentrates on deep understanding of the processes of bifurcation and instability in geoengineering systems. The book covers multiscale processes from the scale of crystals to rocks to rock masses. The book considers a wide range of accompanying phenomena from liquefaction to seismicity and landslides. · Topics covered are: I. Localisation and instability in geomaterials II. Fracturing, failure and seismicity III. Deformation processes Intended readership: Universities and Consulting and Research organisations, research students, academics and engineers working in the fields of geomechanics, rock mechanics and geotechnical engineering.