The objective of this book is to make the fundamental concepts of cytogenetics and Molecular biology and to give an update account of the relevant topics. The topics have been carefully chosen to help students achieve learning objective. Many special features are included to make the book user friendly. Based on our own experiences in teaching cytogenetics and Molecular Biology, they have been implemented and found to be effective in the classroom. The book is eminently suitable for undergraduate and postgraduate students of botany, agriculture, zoology and biotechnology for courses in genetics/genetics and cytogenetics.