Book excerpt: This work describes the solubility, solution properties, thermodynamics, miscibility, solubilization, mesomorphic character and other physical properties of mixed surfactant systems - presenting both theoretical analysis and a wide range of practical applications. Equations clarify complex and abstract constructs.;The book also: treats mixed critical micelle concentrations, surface tension, flotation and absorption in terms of thermodynamic models; explores the miscibility of fluorocarbon and hydrocarbon surfactants in the micelles, covering micelle formation, liquid-liquid solubility and thermodynamics of mixed micellization; determines the mean aggregation number by steady-state quenching methods, and analyzes the composition of mixed micelles; discusses the mechanisms and experimental studies of adsorption from mixed surfactant systems; examines surface activity of surfactant mixtures, mixing phenomena and liquid crystal phase behaviour; and reviews means of investigation that use ion-specific electrodes, light scattering, and NMR and flourescence probing.