Manganese rich austenitic twinning induced plasticity steels with high strength and high ductility have been developed in 1990s as promising candidates for automotive applications. Tremendous efforts have therefore been made to explore the unusual deformation and failure mechanisms of these alloys. We provide here a critical assessment of the recent progress in understanding their deformation and failure mechanisms and discuss some scientific challenges that remain unresolved, for example, a physically based twinning kinetics model.