Genetics is the branch of biology that focuses on the study of genetic variation, genes and heredity in organisms. Some of the major areas of study within this field are trait inheritance and molecular inheritance mechanisms of genes. It also studies the function and behavior of genes. The major sub-fields of genetics include epigenetics, molecular genetics and population genetics. Epigenetics focuses on the study of the heritable phenotype changes that do not involve alterations in the DNA sequence. Molecular genetics studies the function and structure of genes in organisms using genetic screens. Population genetics deals with the genetic differences present within and between populations. This textbook is compiled in such a manner, that it will provide in-depth knowledge about the theory and concepts of genetics. While understanding the long-term perspectives of the topics, it makes an effort in highlighting their impact as a modern tool for the growth of the discipline. This book is appropriate for those seeking detailed information in this area.