Tool wear has been a recurrent problem in the metal machining industry and adversely affects the surface finish of machined components. A good surface finish has a great influence on the worth of products and satisfaction level of consumers. The causes of tool wear and surface defects that put complex limitations on tool life and the surface finish of products have been the subject of a large number of investigations. Tool life is the most important practical consideration in the selection of cutting tools and cutting conditions. Tools, which wear out slowly, have comparatively long service lives, resulting in reduced production costs and more consistent dimensional and surface finish capabilities. The last statement explains why tool life is the most common criterion used to rate cutting tool performance and the machinability of materials. This book should help explains the importance of coating metal cutting tool inserts with hard substances (coatings) especially with TiN, TiC,Al2O3 etc. The book should be especially useful to both undergraduate, graduate /research students for higher degrees above all Industrial Researchers would find this book very useful.