The field of oral microbiology has seen fundamental conceptual changes in recent years. Microbial communities are now seen as the fundamental etiological agent in oral diseases through their interface with host inflammatory responses. Study of structured microbial communities has increased our understanding of the roles of each member in the pathogenesis of oral diseases, principles that apply to both periodontitis and dental caries. Against this backdrop, the third edition of Oral Microbiology and Immunology has been substantially expanded and rewritten by an international team of authors and editors. Featured in the current edition are: links between oral infections and systemic disease revised and updated overview of the role of the immune system in oral infections thorough discussions of biofilm development and control more extensive illustrations and Key Points for student understanding Graduate students, researchers, and clinicians as well as students will find this new edition valuable in study and practice. The field of oral microbiology has seen fundamental conceptual changes in recent years. Microbial communities are now seen as the fundamental etiological agent in oral diseases through their interface with host inflammatory responses. Study of structured microbial communities has increased our understanding of the roles of each member in the pathogenesis of oral diseases, principles that apply to both periodontitis and dental caries.