Gnathology was defined by McCollum and Stuart (1920) as“the science that treats the biologics of the masticatory mechanism; that is, the morphology, anatomy, histology, physiology, pathology and therapeutics of the oral organ, especially the jaws and the teeth and the vital relations of this organ to the rest of the body.” (The Glossary of Occlusal Terms by International Academy of Gnathology, 1979) . On the other hand, the science of occlusion section of the Science Council of Japan, Liaison Committee for Sciences of Occlusion recently defined science of occlusion, tentatively, as“a field which united various sciences aiming 1) to study and clarify morphologically, functionally and kinematically the normal and not normal images and the aging changes of the stomatognathic system including the relation of this organ to the rest of the body, and 2) to apply the results to the diagnosis, therapy, reconstruction and esthetic reproduction.”Since these definitions are substantially the same, it indicates that the concept of Gnathology has penetrated into dentistry throughout this country.However, it must be admitted that since Gnathology, in the process of its realization, had inclined excessively to precise mechanics, its standard procedures could not have applied to every clinical cases. Recently Hobo et al. proposed a new clinical procedure called“Twin-stage procedure”as a first step for the answer to the pending question in Gnathology. Continuously, the Japan Academy of Gnathology hammered out a scheme to expand scientific activities aiming“the elucidation on the relation to the occlusion of 1) the mandibular movement, 2) the maxillomandibular relationship, 3) the physiologic condition of the whole body, including muscular activities, 4) occlusal desease, including temporomandibular disorders, 5) implants, 6) dentures, 7) periodontal desease, 8) prosthodontics, 9) esthetics, and 10) various clinical procedures.” (J Japan Gnatho, 18 (3), 1997)The footprints of Gnathology from the proposition by McCollum (1920) till today (1997) were briefly summarized.