1.Introduction: the significance of radiobiology and radiotherapy for cancer treatment 2. Irradiation-induced damage and the DNA damage response 3. Cell death after irradiation: how, when and why cells die 4. Quantitating cell kill and cell survival 5. Models of radiation response 5. Dose-response relationships in radiotherapy 6. LET and RBE 7. Tumour growth and response to radiation 8. Fractionation: the L-Q approach 9. The L-Q approach in clinical practice 10. Modified fractionation 11. Time factors in normal-tissue response to radiation 12. The dose-rate effect 13. Pathogenesis of normal-tissue side-effects 14. The volume effect in radiotherapy 15. The oxygen effect and fractionated radiotherapy 16. The tumour microenvironment and cellular hypoxia responses 17. Therapeutic approaches to tumor hypoxia 18. Combined radiotherapy and chemotherapy 19. Retreatment tolerance of normal tissues 20.Molecular image-guided radiotherapy with positron emission tomography 21. Molecular-targeted agents for enhancing tumour response 22. Biological response modifiers in the clinic: tumor 22. Biological response modifiers: normal tissue 23. Molecular targeting and patient individualization 24.Protons and other ions in radiotherapy 25. Second cancers after radiotherapy