This first volume provides the basic matters needed for understanding the thermophysical properties of metallic liquids and for developing reliable models to accurately predict the thermophysical properties of almost all metallic elements in the liquid state, together with methods for quantitative assessment of models/equations. The authors also review the structure of metallic liquids, which is based on the theory of liquids, followed by density, volume expansivity, thermodynamic properties (evaporation enthalpy, vapour pressure, heat capacity), sound velocity, surface tension,viscosity, diffusion, and electrical and thermal conductivities. Finally, the essential points of methods used for measuring these experimental data are presented.