This lecture covers the fundamentals of radiative heat transfer, including emissive power, blackbody radiation, Planck's law, and spectral emissive power. It explains the concepts of emissivity, absorptivity, and reflectivity, as well as the laws of reciprocity and Kirchhoff. The lecture also delves into spectral directional and hemispherical emissivity, reflectivity, and the predictions from electromagnetic wave theory.