Abstract-Electro discharge machining (EDM) processis a well-established advanced machining process for producing complex geometry with close tolerances in these materials that are extremely difficult-to-machine by conventional machining processes. EDM process offers a better alternative or sometimes the only alternative for generating accurate three dimensional complex shapes of macro, micro and nano features in difficult-tomachine materials among other advanced machining processes. The success of the EDM process depends upon the selection of appropriate process parameters. The selection of preferred process parameters plays a significant role to ensure quality of product and to reduce the machining cost in computer controlled machining process. Hence, Optimization methods applied for machining process are necessary for continuous improvement of the machining process. The objective of this paper is to offer comprehensive knowledge concerning the optimization of electro discharge machining of superalloys and composites materials.