Radiation therapy, known also as radiotherapy, is widely used in oncology as one of the types of cancer treatment. Radiotherapy, as the name suggests, uses radiation to treat cancer. It may be paired with chemotherapy to achieve better results in cancer treatment. Though the use of radiation for cancer treatment is wide-spread and well-researched, there are still many questions surrounding it. Therefore, we have prepared this easy guide, throughout which we will try to answer some fundamental questions like: “can radiation cure cancer?, “How does radiation therapy kill cancer cells?”, “what to expect after radiation treatment?” and others. We hope that this text will help solve at least some mysteries surrounding radiation therapy.