Genetics can be defined as the study of genes, inheritance of traits and variation in living organisms. It is an essential aspect of biology and provides insights into how evolution occurs. The inheritance of traits in genetics is understood with the tools of pedigree charts, Punnett squares and twin studies. The understanding of genes requires comprehension of gene expression, extra nuclear inheritance, mutation, epigenetics and control of development. Some of the modern focus areas of genetics are alternative splicing, mobile genetic elements, genomics, genetic engineering and horizontal gene transfer. The genetics of human behavior is another area of constant research. The genetic contribution to the development of schizophrenia, autism, ADHD and drug abuse are some of the conditions that are being actively investigated. This book includes some of the vital pieces of work being conducted across the world, on various topics related to genetics. It provides significant information of this discipline to help develop a good understanding of the concepts and applied principles of genetics.