In Placing Outer Space Lisa Messeri traces how the place-making practices of planetary scientists transform the void of space into a cosmos filled with worlds that can be known and explored. Making planets and other celestial bodies into places is central to the daily practices and professional identities of the astronomers, geologists, and computer scientists Messeri studies. She takes readers to the Mars Society's Mars Desert Research Station, showing how scientists transform Earth into a Martian place and use the Utah desert to create narratives of Martian exploration. At NASA Ames, she traces how scientists inscribe within digital maps of Mars senses of place. Messeri also joins scientists at Chile's Cerro Tololo Inter-American Observatory and in MIT's labs as they discover exoplanets and combine telescopic data with their planetary imagination to capture both a planet's past and future and what it would be like to visit and live there. The place-making work of planetary scientists, especially their search for an Earth-like planet, allows us to understand the universe as densely inhabited by evocative worlds, which in turn tells us more about Earth, ourselves, and our place in the cosmos.