The book gives a first-look at radiative transfer in planetary atmospheres with particular attention to the Earth's atmosphere and climate. It aims to upper-division undergraduates and beginning graduate students in physics and atmospheric sciences. This book covers the essence of the raditive transfer of sunlight, treating absorption and scattering, and the transfer of the thermal infrared appropriate for localthermodynamic equilibrium, absorption and emission. The treatment of radiative transfer relies heavily on approximate analytic but useful solutions to the equation of radiative transfer, as opposed to computer modeling and numerical results. This book provides students with analytic tools that allows them to probe the behavior of the solutions, thereby leading them to a better understanding and appreciation for the computer-generated numerical results. While simplifications are used to facilitated analysis, the results provide a fair representation of the behavior of sophisticated numerical simulations. Simplified treatments are combined with optional sections outlining how those simplified treatments can be transformed into more accurate and ultimately to state-of the-art numerical codes in order to highlight the commonalities, differences, and limitations of the simplified treatments. So, while the book is meant to cover the essence of the material in a short 10-week course, the material in the optional sections will facilitate use of the book at the more leisurely pace and in depth focus of a semester course. The authors focus on the Earth's radiative energy budget. Furthermore, they also include some examples of how the solutions of the radiative transfer equation are used in remote sensing to probe the thermal structure and composition of planetary atmospheres.