Periodontal disease affects the mouths of the entire adult population to some degree and causes severe disease in 10 per cent. This is a concise account of the pathological processes involved in periodontal disease, its causes and progression, based on advances in contemporary research. A rational approach to treatment is presented on the basis of these processes. A broad overview of periodontal disease is followed by accounts of the periodontium in health and disease. The book then deals with the micro-organisms implicated in periodontal disease and evaluates their significance. The host responses to factors present in dental plaque are discussed, followed by an account of the interactions between bacteria and the host which cause tissue damage. This leads to a consideration of the different clinical manifestations of the disease, including those associated with HIV infection. In the final chapter, a rational approach to treatment is presented, based on an understanding of the disease mechanisms discussed in the book. The biologically-orientated approach is particularly suitable for dental undergraduates, and those preparing for the Fellowship Examinations of the Royal Colleges. It will be also be valuable for every practising dentist who wishes to update their knowledge of this important and developing subject. No other book deals with the aetiology and pathogenesis of periodontal disease in such a comprehensive, yet straightforward way, making extensive use of diagrams and summary tables to make the subject more easily accessible.