Head gear, though considered primitive, is an important appliance in orthodontic armamentarium. This family of appliance is typically used to restrict the normal downward and forward growth of the maxilla. Maxillary growth is restrained and/or redirected so that basal bones become more harmoniously related to one another as the unimpeded mandible "catches up" during normal growth. This book focuses on different types of head gears and the biomechanics involved.