MQL is the possible solution in the machine shops in respect of environmental friendliness,workers health consciousness,cost effectiveness.MQL application works favorable in respect of power consumption, product quality and tool life.The work has been taken up to explore the role of MQL on the major machinability characteristics in turning 42CrMo4 steel by coated carbide tools.Chapter 1 presents the general requirements in machining industries, role of cutting tools and problem associated with high cutting temperature, selection of cutting fluids and expected role of MQL.Chapter 2 presents the procedure and conditions of the machining experiments.The experimental results on the effects of MQL relative to dry machining on cutting temperature, chip morphology, cutting forces, cutting tool wear and surface roughness in turning alloy steel under different cutting conditions.Chapter 3 presents the discussion on experimental results obtained under different environments.Chapter 4 contains the concluding remarks and also provides some recommendations for future work.