Cancer is a leading cause of death worldwide. More than 10 million people die each year from this disease, but many cancers can be cured if detected early and treated effectively. In fact, the overall cancer survival rate has improved significantly since 1991 with the hard work of physicians and researchers, improved testing and screening technology, and lifestyle changes by those who are at greatest risk from the disease. Despite these positive trends, many people view cancer as a scary disease and have many misconceptions about the causes, treatments, and outcomes for those with cancer. What Is Cancer? explores the causes of cancer, diagnosis methods, treatment options (e.g., surgery, chemotherapy, radiation treatments, immunotherapy), the effects of a cancer diagnosis on one's mental health, and methods of cancer prevention. It also provides annotated lists of useful cancer organizations, which provide additional assistance to cancer patients and caregivers. Understanding Cancer provides a fact-based examination of the various types and causes of cancer, treatment options (including emerging approaches such as gene therapy), methods of reducing the risk of being diagnosed with cancer, and how to care for loved ones with cancer. Stories of those who are battling cancer, as well as their caregivers, are also featured in the series in order to humanize this disease.