Disconnections are interfacial defects with dislocation and step character; for example, twinning dislocations in homo-phase and transformation dislocations in hetero-phase materials. They play important structural roles and are classified as either 'perfect', separating energetically degenerate regions of interface, or 'partial', bounding a faulted region. In kinetic mechanisms, disconnection motion can be glissile, by conservative climb or climb. In the present paper, disconnection mobility is analyzed in terms of shear and shuffletype atomic displacements and diffusional flux. This is applied to a sequence of hetero-phase materials with increasing structural complexity, namely the to transformation in Ti, 0 precipitation in Al(Cu) and the orthorhombic to monoclinic martensitic transformation in ZrO 2 . A disconnection source mechanism in Ti, involving conservative climb, is also described.