Several state-of-the-art applications of molten salts are presented, such as metal-molten salt systems, room temperature glass formation, and room temperature melts. Several recent examples of applications highlight the importance of molten salts in various industries (batteries, pyrochemical reprocessing of nuclear fuel, synthesis and catalysis). The basic concepts of the structure, dynamics, electrochemistry, interfacial and thermodynamic properties are detailed and relevant experimental methods described. Such fundamental concepts are essential for an in-depth understanding of the physicochemical properties of molten salts in general, including metal-molten salts, glass forming and low temperature melts. Experimental methods for investigating structural, dynamical, electrochemical thermodynamical and interfacial properties are detailed, as also are techniques for data collection and analysis. Scientists, engineers and technologists will find the volume a valuable reference source covering a wide spectrum of fundamental concepts and modern technologies.