This is the ideal book for anyone contemplating starting a career in, or shifting their career to, studying the dynamics that drive cancer progression and its response to therapy. Topics include the theory and population genetics of cancers, genetic diversity within tumors (intra-tumor heterogeneity), understanding how mutant clones expand in tissues, the role of cancer stem cells in the dynamics of tumors, the evolution of metastasis, and how to improve cancer therapy by addressing the evolution of cancers in response to our interventions. There are also chapters on the patterns of cancer susceptibility in humans due to a mismatch between our modern environment and the environment in which our ancestors evolved, as well as a chapter on the evolution of cancer suppression mechanisms that have evolved in different species, particularly the large long-lived animals like elephants and whales that are better at suppressing cancers than humans. This book serves as a primer on the evolutionary and ecological theory of cancer- the framework upon which all the details of cancer may be hung. It is ideal for oncologists and cancer researchers interested in evolutionary theory, and evolutionary biologists and ecologists interested in gaining insights into cancer development and prevention. .