Carcinogenesis is a multi-disciplinary task designed to bring together all the varied aspects of research which will ultimately lead to the prevention of cancer in man. Therefore to understand the pathogenesis of oral cancer, carcinogenesis is one of the means in improving the diagnostic, prognostic and treatment modalities. Cancer being a major public health issue in the developing world, requires an in depth knowledge of the mechanism of genetics of cancer at the cellular/molecular level. So this Book will try to cover all the major research work already done on carcinogenesis throwing light in the areas of viral, physical and chemical carcinogenesis and mutagenesis; factors modifying these processes such as DNA repair, genetics and nutrition; metabolism of carcinogens; the mechanism of action of carcinogens and of environmental carcinogens and promoting agents; epidemiological studies; and the formation, detection, identification and quantification of environmental carcinogens. Advances in our basic understanding of the biology of cancer could play a valuable role in the future control of oral cancer.