The problem of radiation induced tumors is explained in detail in the following chapters: 1. Malignant tumors in dial painters using luminous paint, 2. Malignant tumors after injection of Thorotrast, 3. Bronchial tumors in Uran-mineworkers, 4. Malignant tumors caused by radium-compresses and radium-moulages, 5. Thyroid cancer caused by irradiation, 6. Leukemia and malignant tumors following the atomic bomb detonation in Hiroshima and Nakasaki, 7. Malignant tumors in Lupus vulgaris, 8. Development of malignant tumors following the irradiation of praecancerous alterations, of benign tumors and other benign changes in head and neck, 9. Radiation induced soft-tissue and bone sarcoma in the skull, 10. Radiation-induced cancers in hypopharynx diverticula, 11. Radiation-induced cancers in the antethoracic skin graft esophagus, 12. Radiation-induced second-tumors, 13. Cancer caused by ultraviolet rays, 14. Increase of hematogenic metastases by irradiation. 15. Malignant tumors caused by irradiation of the fetus in utero.