Emulsions are the next most widely used adjuvants in human vaccines after alum-based formulations. Their importance in modern vaccines is underscored by their demonstrated record of stability, safety, and enabling of antigen dose-sparing. The book includes an introduction addressing a historical perspective and exploring currently available adjuvants. The book then profiles two leading emulsion adjuvants for human use: MF59® (Novartis) and AS03 (GlaxoSmithKline) and concludes with an overview of innovations in technology covering next-generation emulsions. Together, the chapters in this volume provide a snapshot of emulsion adjuvant history, current human use and safety, and future development directions.