When scientists discovered the first ocean beyond Earth, they had two big questions: "Is it habitable?" and "How do we get there?" Thus began a team's 20-year odyssey to mount a mission to Europa, the ocean moon of Jupiter. Standing in the way was NASA and Congress, both preoccupied with Mars; the White House, quick to cut the budget; and even Jupiter itself, enveloping its moon in a radiation belt. Providing a view of the inner lives of scientists who study the solar system's mysterious outer planets, David Brown chronicles the remarkable saga of how Europa was won, and what it takes to get things done—both down here, and out there.