The essentials of planetary atmospheres of the solar system are concisely reviewed, including their thermodynamics, radiation, chemistry, and dynamics. First, the diversity of atmospheric composition and basic physical properties is described, including the vertical structure. The composition, in turn, affects the climate through energy transfer and the greenhouse effect. So next, the radiative transfer of energy is discussed, including absorption and emission by atmospheric gases. A brief overview of photochemistry provides an appreciation of the composition and vertical distribution of atmospheric constituents. Basic principles of atmospheric motion are then discussed. Finally, some outstanding questions are noted.