Esophageal cancer is malignancy of the esophagus. Esophageal tumors usually lead to dysphagia (difficulty swallowing), pain and other symptoms, and are diagnosed with biopsy. Small and localized tumors are treated with surgery, and advanced tumors are treated with chemotherapy, radiotherapy or combinations. This book presents an in depth look into the identification and treatment of esophageal cancer. This includes identification of esophageal squamous cells, epidemiology of esophageal cancer, atypical regenerative hyperplasia of the esophagus, genomic instability and gene therapy.