The Cell Cycle is an account of the mechanisms that control cell division, beginning with a description of the phases and main events of the cell cycle and the main model organisms in cell-cycle analysis, including Xenopus, Drosophila, and yeasts. Later chapters focus on the molecules and mechanisms of the cell-cycle control system, including the cyclin-dependent kinase family of protein kinases, the cyclins that activate them, and the signaling molecules that regulate them, and discuss cell-cycle control in development and the failure of controls in cancer.