This book addresses major problem in the management of patients with cancer of the head and neck. The authors have written six chapters of particular importance for head and neck cancer diagnosis, treatment, and rehabilitation. Chapter 1 describes treatment of patients with squamous cell carcinoma of the head. Chapter 2 presents treatment of patients with squamous cell carcinoma of the neck. Biochemical studies of head and neck cancer treatments are presented in Chapter 3. In chapter 4 biochemical studies of head and neck cancer biomarkers are presented. Photodynamic therapy (PDT) exploits light interactions and photosensitizers to induce cytotoxic reactive oxygen species. Photodynamic diagnosis (PDD) uses the phenomenon of photosensitizer emitting fluorescence to distinguish some tumours from normal tissue. PDT offers a therapeutic solution that has been found to be cost-effective compared to palliative major surgery or chemotherapy. However, despite the significant improvement noted in preclinical and clinical trials, PDT is still not considered the standard treatment option for head and neck cancer. Multiple photosensitizers have been studied and tumours have been treated in a variety of head and neck sites over the last 30 years. Photodynamic therapy is a palliative treatment option for head and neck squamous cell carcinoma patients which induces local inflammation and alters tumour cell morphology.