The usage of drugs to treat cancer is termed as chemotherapy. It is aimed at killing the cancer cells or stopping their growth and spread to other parts of the body. There are several mechanisms through which it can work such as by destroying both non-cancerous and cancerous cells, attacking only cancer cells, and fighting the genes of the cancer cells in order to kill them and stop their spread. The different types of chemotherapy drugs are alkylating agents, antimetabolites, mitotic inhibitors, topoisomerase inhibitors and steroids. The drugs given to cure cancer are selected on the basis of the type of cancer, whether the patient has a history of cancer, and other health issues such as kidney, liver or heart disease. This book attempts to understand the multiple drugs that are used to treat cancer and their diagnostic and therapeutic applications. The various studies that are constantly contributing towards advancing technologies and evolution of this field are examined in detail. The book is appropriate for students seeking detailed information in this area as well as for experts.