Explore the fascinating atmospheres of terrestrial planets in this 31-minute lecture from Spahn's Science Lectures. Delve into the unique characteristics of the Moon, Mercury, Mars, and Venus, examining their atmospheric compositions, processes, and evolution. Learn about the source and loss mechanisms on the Moon and Mercury, the presence of water on these bodies, and the complex Martian atmosphere, including its winds and climate patterns. Investigate the intriguing loss of Mars' atmosphere and how the planet's size played a crucial role. Finally, uncover the mysteries of Venus' dense atmosphere, its outgassing processes, and the runaway greenhouse effect that shaped its current state.