This book is related to the multi-response optimization of the CNC turning operation.In present research work, the effect of insert nose radius and machining parameters including cutting speed, feed rate and depth of cut on surface roughness(Ra) and material removal rate(MRR) in a turning of HSS(M2) are investigated using the Taguchi method and ANOVA. A three level, four parameter design of experiment, L9 orthogonal array using Minitab 14 software, the signal-to-noise (S/N) ratio is employed to study the performance characteristics in the turning of HSS(M2) by taking nose radius of Tin coated carbide inserts tool of 0.4, 0.8 and 1.2 mm on CNC turning centre. The analysis of variance (ANOVA) is applied to study the percentage contribution of each machining parameters while CNC turning of HSS (M2) material. All experimental trials are conducted in a dry machining environment and at a constant spindle speed of 2800 rpm. The results are verified by taking confirmation experiments. The present investigation indicates that feed rate and nose radius are the most significant factors in the case of material removal rate and surface roughness.