Orthodontic study models are accurate plaster reproductions of the teeth, alveolar process and their surrounding soft tissues. They are essential diagnostic records, which allow examination of teeth and the occlusion from all directions. They are invaluable tools required for orthodontic diagnosis, treatment planning, and fabrication of orthodontic appliances. Orthodontic study models are also used for patient education and monitoring the progress of orthodontic treatment. The study models are required for fabrication of orthodontic appliances such as removable orthodontic appliances, myofunctional appliances, habit breaking appliances, space maintainers, space regainers, guards, molar bands and for indirect bonding. The book explains the significance of study models in orthodontic practice, types, various methods of fabrication and their duplication. Recent advances including digital orthodontic study models, photographic modificaton of Kesling''s setup are also addressed.