THE FARTHEST tells the captivating tales of the people and events behind one of humanity’s greatest achievements in exploration: NASA’s Voyager mission, which celebrates its 40th anniversary this August. The twin spacecraft—each with less computing power than a cell phone—used slingshot trajectories to visit Jupiter, Saturn, Uranus and Neptune. They sent back unprecedented images and data that revolutionized our understanding of the spectacular outer planets and their many peculiar moons.