This book presents the work on optimization of turning parameters in machining of AISI 304 steel. AISI 304 stainless steel is called "Hard - to - cut" material due to its low thermal conductivity and strain hardening effect. The nano AlTiN/Si3N4 coated tools show excellent performance in machining when compared to conventional TiN and TiAlN coated tools. This work presents the method to evaluate the tool wear and also optimize the machining parameters using "Grey Relational Analysis".