Surface hardening is one of heat treatment processes which include a wide variety of techniques. Striving at improving the wear resistance of parts without affecting the interior softness and toughness of the part.The surface hardening of steel has an advantage over through hardening because it is less expensive, low-carbon and medium-carbon steels can be surface hardened with problems of less distortion and cracking associated with the through hardening of thick sections. Electrolytic surface hardening process has been found as a new development in the area of surface heat treatments. The book covers the electrolytic surface hardening process using specimens of medium carbon steel AISI 1050. For this purpose, an apparatus has been built to perform the necessary systematic investigations to explore the possibilities and capabilities of this promising surface hardening process.