Book excerpt: Our understanding of the etiopathology of periodontal disease has changed greatly over the last decade. The huge diversity of species within the microbial biofilm and the enormous multi-layered complexity of the innate, inflammatory and adaptive immune responses generated in response to it warrant study and discussion. Comprising reviews from renowned experts in the field, this book presents a comprehensible overview of this exciting and pertinent subject matter. It provides new insights into the structure and composition of subgingival biofilms and the nature of the extracellular matrix. Further, a summary of current understanding of subgingival microbial diversity and an overview of experimental models used to dissect the functional characteristics of subgingival communities are presented. Other articles discuss the innate cellular and neutrophil responses to the periodontal biofilm. The role of antimicrobial peptides in the host response to biofilm bacteria and modern approaches to nonsurgical biofilm management are also discussed. Finally, this volume addresses advances in antibiotic use and proposes a paradigm shift in the pharmacological approach to periodontal disease management.