Molecular Biology is the existing and fast moving field of science, and is condensed into but balanced review. In the last two decades the field of Molecular Biology has undergone a variable Revolution leading to major advances in our understanding of cell structure and function at molecular level. The convergence of cytological Genetic and Biochemical approaches has generated a rich panorama of detail, the significance of which we are still attempting to unravel. The present title is being written as an introduction of this rapidly growing field. Our goal is to acquaint the undergraduate Student who is encountering the subject for the first time with the fundamental principles that characterize the molecular Organization of cell. Molecular Biology of the cell is chiefly concerned with Eukaryotic cells, as opposed to Bacteria, and its title reflects the prime importance of the insights that have come from the molecular approach. The eukaryotic Cells that form multicellular Animals and Plants are social Organisms to an extreme degree, the live by cooperation and specialization.