Periodontitis involves an inflammatory process, of multifactorial origin, affecting the periodontal tissues. Loss of alveolar bone support is one of the characteristic signs of destructive periodontal disease and is generally considered to represent the anatomical sequela to the apical spread of periodontitis. Intimate knowledge of all bony defects associated with periodontal disease is essential. So this book is aimed at classification and deep insight which will be helpful for proper diagnosis and treatment of periodontal osseous defects.