This book will review old and new methods to study emulsion stability and structure. Examples of emulsion-based foods include ice cream, yoghurt, and mayonnaise. Several techniques are used to study the physical behavior and structure of emulsions. More recently, other techniques, such as ultrasound profiling, microscopy, droplet size distribution, and measurement of surface concentration to characterize adsorbed protein at the interface, have also been employed. Some of these techniques, such as droplet size distribution, involve some form of dilution. However, dilution disrupts some structures that play an important role in stability. The ability to study the stability of food emulsions in their undiluted form may reveal subtle nuances about their stability. Diffusing wave spectroscopy (DWS), laser scanning confocal microscopy (LSCM), nuclear magnetic resonance (NMR), and Turbiscan are among the more powerful, non-perturbing techniques used to characterized emulsions.