The primary objective of this trial is to determine whether the Talent Thoracic Stent Graft, an investigational device, is a safe and effective method of treating thoracic aortic aneurysms (abnormal ballooning of the vessel wall) and other thoracic lesions (dissections, transections, pseudoaneurysms, penetrating ulcers, etc.). The endovascular method is a substitute for the major operation that is performed to treat the lesions.