Understanding Cancer is a brand new undergraduate textbook for students without prior training in biology that integrates an introduction to cancer medicine with descriptions of the biological processes that go wrong to cause cancer’s onset and progression. It also highlights the human side of cancer with stories of patients and loved ones touched by the disease, dealing with diagnosis, treatment, and the prospect of death as well as the broader societal aspects of cancer and its prevention. Key discoveries that have improved our understanding of cancer are presented in sidebars. In spite of this diversity, the book maintains precision and simplicity in describing what is and is not known about cancer, describing the strengths and limitations of current treatments