Cell cycle checkpoints control the fidelity and orderly progression of eukaryotic cell division. By controlling the orderly progression of critical cell cycle events such as DNA replication and chromosome segregation and ensuring proper repair of damaged DNA, cell cycle checkpoints function to ensure genome integrity. Mechanisms of checkpoint controls are not only the research focus of investigators interested in mechanisms that regulate the cell cycle, but are also the interests of researchers studying cancer development as it is increasingly clear that loss of cell cycle checkpoints, which leads to genomic instability as a result, is a hallmark of tumorigenesis. provides detailed descriptions of methodologies currently employed by researchers in the field, including those commonly used in the mammalian, yeast, , and model systems. Each chapter describes a specific technique or prool, such as a method to induce cell cycle checkpoints in a particular model system, to synchronize a population of cells to allow observations of cell cycle progression, to identify genes involved in checkpoint regulation, and to study particular protein components of cell cycle checkpoint pathways. Written in the highly successful series format, chapters contain introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory prools, and notes on troubleshooting and avoiding known pitfalls.