There have been many technological developments in clinical orthodontic practice since the last edition of this textbook. The design and construction of orthodontic appliances have changed reflecting the availability of new materials, and as techniques have improved so have the divisions of skills between the specialist, the general dentist and the technician. This second edition of A Textbook of Orthodontics brings together new knowledge and current thinking. The text, with the addition of 130 new illustrations, has been revised to include enlarged sections on case assessment, treatment need and treatment planning. The principles of removable and fixed orthodontic appliance treatment have been updated as has the chapter on post treatment retention. Functional appliances and the place of surgery in the treatment of gross malocclusion and facial deformity are also discussed. There is a new chapter on the principles of treatment for patients suffering from cleft lip and palate.