Common factors that lead to treatment failure in head and neck cancer are the lack of tumour oxygenation, the accelerated division of cancer cells during treatment, and radioresistance. These tumour-related challenges and possible ways to overcome them are covered in this book, authored by three medical physicists and a clinical oncologist who explain how different radiobiological findings have led to the development of various treatment techniques for head and neck cancer. Novel treatment techniques as supported by current scientific evidence are comprehensively explored, as well as the major challenges that arise in the retreatment of patients who have already undergone a form of radiotherapy for primary head and neck cancer.