Gastroscopy, the endoscopic examination of the interior of the stomach, has finally come of age. Although beset with multiple difficulties, and slow to develop, the method has achieved a sudden flowering in the past 10 years found in few other types of examination of the living human. The advances, the results of great interest and perseverance by many workers in all parts of the world, have been based on the happy combination of these efforts and the rapidly changing manufacture of various instruments to visualize, photograph, and biopsy all parts of the stomach at will. So rapid have been these advances that it has been difficult even for those intimately involved to keep abreast of the changes. The general physician public is in consequence still in considerable ignorance of what is now endoscopically available for the diag- nosis of gastric disease. Many interesting types of gastric pathology have been and are still being better defined by endoscopy, but its particular value lies in the diagnosis of malignant neo- plasia of the stomach. Whereas in the immediate past it was necessary to restrict examination to roentgenograms, at best an indirect means, it is now possible to visualize lesions, photograph them in color, and biopsy all suspicious areas with great accuracy. A visual and histologic diagnosis of cancer of the stomach may be made in well-equipped institutions in an hour or less.