This book is focused on electrical discharge machining (EDM) fundamentals. These are the items common to all EDM machines. Fundamentals are concerned with the spark, how the spark is controlled, what causes overcut, and the importance of the dielectric fluid. With regard to the workpiece, fundamentals consider what effect the spark has on the metallurgy and how the surface finish is produced and controlled. The book also describes the development of EDM, the EDM machining system and process, the EDM sparking system, the power supply (generator), spark voltage, electrode servo systems, dielectric systems, ionization and electrode wear, chips, the EDM surface, DC arcing, different kinds of EDM, automatic servo system operation, and electromagnetic radiation. This text will serve as the primer on the EDM machining process, allowing the people using EDM to become more efficient and the machines more productive.