The book deals in initial chapters with introduction, structure of chromosome and its abnormalities. In this edition, efforts have been made to add information regarding a brief history of genetics and classification of chromosome. In the chapter of chromosomal abnormalities, attempt has been made to provide information related to more genetic syndromes. For better understanding of various chromosomal abnormalities, the text is augmented with related illustrations. The other chapters serve topics on genes, inheritance, population genetics, prevention and treatment of genetic diseases. The study of patterns of inheritance is important for the diagnosis, prognosis and estimation of the recurrence risk in other family members. To make it more understandable, different types of inheritance are presented with pedigree analysis. Emphasis has also been made on latest techniques for prenatal diagnosis. The present edition gives an overview of the Human Genome Project, which is the most ambitious project of biomedical researches.