Abstract: Recent observations on the dynamics of crack andfault rupture are described, together with related theoryand simulations in the framework of continuum elastodynamics.Topics include configurational instabilities of tensile crackfronts (crack front waves, disordering, side-branching), theconnection between frictional slip laws and modes of rupturepropagation in earth faulting, especially conditions forformation of self-healing slip pulses, and the rich faultingand cracking phenomena that result along dissimilar materialinterfaces due to coupling between slippage and normal stressalteration.