Every living entity copies its genetic and molecular instruction on its genes and passes on the information to its offspring. At the same time there are differences which creep in among siblings, children, etc. There are some genetic bases for occurrence of certain diseases. The study of all these is included in the subject of genetics. Genetic counselling is the main area where a nurse or healthcare professional can function effectively. This book will provide them a firm knowledge base to learn the basics and also apply them in their professions for the benefit of the patients in particular and society in general.