The destabilizing effects of high intensity AC electric fields on water-in-oil emulsions have been used industrially for almost a century. Several new emulsion-based applications are also receiving attention, including solvent and liquid membrane extraction. However, despite a relatively rich literature, some aspects of the electrostatic separation process are not well understood, with various field types (AC, DC and pulsed DC) and seemingly contradictory findings adding to the complexity and thereby preventing a detailed understanding. In the present work, after a review of the process and its applications, new results for AC and pulsed DC fields are presented to aid discussions on the intensification and utilization of this important phenomenon.