Each year in the United States, about 29,000 people learn they have cancer of the oral cavity (the mouth and lips) or the oropharynx (the part of the throat at the back of the mouth). This issue discusses possible causes, symptoms, diagnosis, and treatment of the disease. Chapters include molecular biology, epidemiology and risk factors, early detection methods, chemoprevention, radiation therapy, surgical management, dental issues, pathology of malignant and premalignent lesions, imaging, and future trends.