Mixing in the ocean interior clearly draws its energy from the internal wave field. The pathway is often described as “Internal wave breaking“, contrary to the observation that the smallest vertical internal wave scales are larger than the largest turbulence scales. Evidence for a different pathway is reviewed here: Internal waves generate patches of LAST, “layered stratified turbulence”, a well-characterized class of motions distinct from internal waves and three-dimensional turbulence. LAST dominates the dynamics in the ‘–1’ range of vertical wavenumbers between internal waves and turbulence. It is possibly generated at transient critical layers, cascades energy to smaller scales and dissipates by generating patches of turbulence and mixing through shear instability. The existence of such patches is well-documented and the limited data suggests that they produce most of the mixing. The mixing efficiency is set by the properties of LAST, not the properties of internal waves.