Chemotherapy is a form of cancer treatment which uses anti-cancer drugs as part of a cancer treatment regimen. It may be administered with a curative intent or as a palliative therapy for prolonging life and managing symptoms. Chemotherapy drugs directly affect the immune system. They are applied to target the overactivity of the immune system as in the case of diseases such as multiple sclerosis, rheumatoid arthritis, vasculitis and systemic lupus erythematosus, among others. Radiation therapy or radiotherapy (RT) is a cancer therapy that uses ionizing radiation to kill or control malignant cells. It is used to target cancer that is localized to a certain area of the body, or to prevent tumor recurrence after surgery. It can be used in combination with chemotherapy. Like chemotherapy, radiotherapy administration also varies for curative, palliative, adjuvant or neoadjuvant therapeutic intent. This book covers in detail some existing theories and innovative concepts revolving around chemotherapy and radiotherapy. It is a valuable compilation of topics, ranging from the basic to the most complex advancements in these fields. For all readers who are interested in oncology and cancer care, the case studies included in this book will serve as excellent guide to develop a comprehensive understanding.