Abstract Recent research has had a most favorable influence upon our concept as to the causes of malocclusion. In fact, our present concept assures a more adequate understanding of our problems and gives us a more positive approach to case analysis and treatment planning. The most noteworthy results of recent research, concerning the structures of the face and jaws, may be summarized as follows: 1. 1. Interstitial bone growth does not exist. Growth of cartilage in the mandibular condyle does occur by interstitial proliferation and by apposition from the deepest layers of the covering fibrous tissue. 2. 2. At no time in the life of an individual do heredity and environment operate alone. 3. 3. All the inherent factors and environmental influences must be maintained in perfect and normal balance for the normal development of occlusion. 4. 4. Growth of bone in the maxilla and mandible is one of the forces of eruption. 5. 5. The present concept discards Dr. Angle's postulate concerning the integrity of the thirty-two teeth in many cases of malocclusion. 6. 6. No growth takes place in the body of the mandible anterior to the first molars after their eruption. 7. 7. All bone growth occurs by surface addition. Orthodontic therapy will not stimulate bone growth. 8. 8. Stability of the dentition is dependent upon correct positioning of the teeth over foundation bone. 9. 9. Permanent and lasting results in establishing esthetic and functional occlusion depend upon the structural limitations of inheritance, environment, and functional adaptation.