During the past few decades, much research has been reported on the formation of insoluble monomolecular films of lipids and biopolymers (synthetic polymers and proteins) on the surface of water or at the oil-water interface. This interest arises from the fact that monomolecular film studies have been found to provide much useful information on a molecular scale, information that is useful for understanding many industrial and biological phenomena in chemical, agricultural, pharmaceutical, medical, and food science applications. For instance, information obtained from lipid monolayer studies has been useful in determining the forces that are known to stabilize emulsions and biological cell membranes. The current texts on surface chemistry generally devote a single chapter to the characteristics of spread monolayers of lipids and biopolymers on liquids, and a researcher may have to review several hundred references to determine the procedures needed to investigate or analyze a particular phenomenon. Furthermore, there is an urgent need at this stage for a text that discusses the state of the art regarding the surface pheqomena exhibited by lipids and biopolymers, as they are relevant to a wide variety of surface and interfacial processes.