This lecture covers the principles of radiative transfer, focusing on the interaction of solar radiation with Earth's atmosphere. Topics include the greenhouse effect, absorption and scattering of radiation by atmospheric constituents, and the role of greenhouse gases in Earth's energy balance. The lecture also discusses the impact of aerosols and clouds on radiation transmission and the greenhouse effect processes. Key concepts such as the Planck function, Stefan-Boltzmann Law, and Earth's emission seen from space are explained in detail.