Cancer is one of the fatal diseases affecting the worldwide population. It is a group of diseases characterized by the uncontrolled development and proliferation of irregular cells. It is unfortunate that many cancers still lack proper screening strategies. If the spreading will not be controlled, it may influence life. Diagnostic work-ups, healing methods, and outcomes of treatment are not uniform for all cancers. The regulation of cancer requires the effective implementation of knowledge derived from many years of positive study. It is now known that over one-third of cancers are preventable, and one-third possibly curable, provided they are diagnosed early in their direction. The quality of life of patients with incurable conditions will also be increased with soothing care. In the present chapter, comprehensive details of cancer and its different characteristics, features, types, and causes are discussed.