Evolution begins with the inheritance of gene variations.This book presents an essential understanding of the basics of genetics and its link with various disorders and dental diseases.Genetic risk factors, lifestyle and environmental factors play a vital role in diseases such as Periodontitis and Peri-implantitis.Identification of genetic factors that control the immune response to various microbial infections in both human and animal models have been increased and more emphasis on genetically determined host responses is focused.The authors have tried to cover wide areas of correlation between recently identified genetic polymorphisms and immune response phenotypes found in certain groups of periodontitis patients.The book also includes the new developments in genetics that are currently accumulating at an unprecedented rate helping us in finding newer diagnostic and treatment modalities.This text shall hence broaden the thinking horizon of dental practitioners and specially the post graduates for early detection of predisposition to disease or finding and correcting the genetic etiology behind various diseases