Cytology refers to a branch of pathology, the medical specialty that deals with making diagnoses of diseases and conditions through the examination of tissue samples from the body. Cytology, more commonly known as cell biology, studies cell structure, cell composition, and the interaction of cells with other cells and the larger environment in which they exist. The term "e;cytology"e; can also refer to Cytopathology, which analyzes cell structure to diagnose disease. Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person's chance of developing or passing on a genetic disorder. More than 1,000 genetic tests are currently in use, and more are being developed. Molecular Cytogenetics encompasses all aspects of chromosome biology and the application of molecular cytogenetic techniques in all areas of biomedicine, including structural and functional organization of the chromosome and nucleus, genome variation, expression and evolution, chromosome abnormalities and genomic variations in medical genetics and tumor genetics. Molecular Biology has been written with the view of presenting a coherent, enlightening work on the topic by means of which experts may approach the subject with an expert reader may approach the subject with an eager constitution. Molecular biology deals with one of the most rapidly progressing areas of biology, it remains critical for students not only to have the most current information available, but also to understand the experimental nature of contemporary research in cell and molecular biology. It is our earnest hope that this book will be of great value to all the students