Apparatus and methods for capsule endoscopy are described for locating, positioning, steering, aiming and tracking of an endoscopy capsule (100) within a patient's esophagus and stomach. The apparatus includes an endoscopy capsule (100) with a magnetic element (110), an external capsule positioning system (200) including at least one magnet (202) movable along a track (204) for positioning the endoscopy capsule (100) within a patient. Also described are apparatus and methods for performing endoscopic spectroscopy using different wavelengths of light and other imaging technologies to diagnose various disease conditions, such as premalignant or inflammatory changes and internal bleeding.