Synopsis In the last two decades the field of cell biology has undergone a veritable revolution, leading to major advances in our understanding of cell structure and function. 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 to this rapidly growing field. One of the major concerns of this title is to provide students with basic understanding of what a cell is and why the cell is the fundamental unit of life. Our approach throughout has been to focus on the major question involved and the experimental approaches utilized in addressing these questions.