Mice are a useful model system for exploring how cancer develops, progresses, and may be treated. Studies of genetically engineered mouse models (GEMMs) and mice bearing patient-derived xenografts have yielded important insights into the biology of human cancer, and new technologies have moved the field forward significantly in the past decade. Written and edited by experts in the field, this new volume from Cold Spring Harbor Perspectives in Medicine reviews the wide variety of mouse cancer models that have been developed and the ways in which they are improving our understanding of cancer and creating new therapeutic opportunities. The contributors discuss the various genetic techniques used to make mouse models and the plethora of GEMMs representing most common cancer types. They explain how our knowledge of the cell cycle, tumor metabolism, and cancer cell plasticity has benefited the field, as well as insights into the role of the microenvironment and the immune system. The authors also examine more sophisticated models being leveraged to investigate drug responses and phenomena like tumor dormancy. Other chapters cover technical advances, such as high-throughput studies, CRISPR genome engineering, and advanced imaging approaches that make it possible to track individual cancer cells. The book will therefore be of interest not only to cancer biologists but cell and developmental biologists interested in how cellular behavior can become deregulated in pathological conditions.