Radiotherapy is the primary treatment modality or an important adjunct treatment for many patients with H&N carcinoma. Local control is directly related to dose and to the technical accuracy with which the dose is delivered to the target volume. Traditional radiotherapy techniques result in significant doses being delivered to normal tissues adjacent to the target, including the spinal cord and salivary glands. This leaves the patient with significant acute and late normal tissue toxicity that impacts on both the ability to tolerate the actual treatment and on the patient's long-term quality of life. Recently, the investigators have used static conformal multisegmental intensity modulated radiotherapy (IMRT) for a comprehensive irradiation of head and neck cancer with dose sparing of uninvolved tissues. This has resulted in substantial preservation of major salivary gland function in many patients with primary sites in the oral pharynx, oral cavity, nasopharynx, and pyriform sinus. While the investigators' results to date have shown promising preservation of salivary flow, they do not know whether patients treated with IMRT have similar local control rates as those treated with standard radiotherapy. Some investigators have raised the concern that by giving a low radiation dose to areas adjacent to the target volume there is a risk of undertreating the disease. On the other hand, the IMRT delivered with this protocol (called "simultaneous integrated boost", or SIB) may improve local control rates by delivering the same biologically effective dose in a shorter overall time period. This is a phase I/II trial which seeks to establish the efficacy of IMRT for H&N cancer treatment, and to further investigate the relationship between radiation dose to the parotid glands, salivary flow, and quality of life.