Damage and failure of deformable solids is a constantly evolving scientific field which poses a real challenge in terms of comprehension, control and modeling. Driven by different industrial sectors, the research devoted to the study of the physical mechanisms responsible for damage and fracture of engineering materials like metals, polymers, ceramics and composites under extreme loading conditions has been especially prolific over the last decade. Nevertheless, despite the significant efforts spent by scientists in increasing their understanding of the processes of strain localization, damage and failure, it is clear that a number of scientific questions remain open. Within this general theme, three main areas will be covered in this Colloquium: (1) experimental and numerical techniques, (2) material, spatial and temporal length scales and (3) failure mechanisms.