Book excerpt: The association between periodontitis and systemic diseases has become a hot topic in recent years. This comprehensive book reviews the clinical evidence and biological plausibility of the many systemic diseases that have been linked to periodontitis. Edited by Dr Josefine Hirschfeld and Prof Iain L.C. Chapple, experts in each field discuss the mechanisms at work, citing the available key literature and clearly summarising current knowledge and understanding of the associations between periodontitis and diabetes mellitus, cardiovascular diseases, chronic kidney disease, inflammatory bowel diseases, rheumatoid arthritis, respiratory diseases, pregnancy and fertility, malignancy, neurodegenerative diseases, stress and depression, and autoimmunity. Each chapter critically appraises the existing evidence, providing comprehensive, contemporary and well-considered insights into the clinical evidence and biological plausibility of each condition, as well as the limitations of existing studies and how these can be overcome in the future. Periodontitis and Systemic Diseases: Clinical Evidence and Biological Plausibility is an indispensable reference for both clinicians and researchers.