At the end of World War II, the Jet Propulsion Laboratory was at the crossroads. Should this outgrowth of Caltech continue to build rockets for U.S. Army in peace time? The answer came with the coming of the Cold War. Yet by 1956, JPL was already seeking a new role and had set its ambitions on teaming with the Redstone Arsenal in Huntsville to launch the first satellite into space. Denied that opportunity in 1956 by the Eisenhower administration, JPL and the Von Braun rocket teams could only watch in frustration as the Soviet Union launched Sputnik, the world's first satellite, in October 1957. Following Sputnik and with the explosion of the U.S. Vanguard rocket just weeks later, the White House, in desperation, turned to the JPL and Huntsville team, which then successfully launched Explorer 1 into orbit less than 90 days after being given the go-ahead. JPL and the Beginnings of the Space Age charts the transformation of JPL from a provider of ballistic missiles to the moment it set out on the path to become the world's preeminent explorer of the solar system and beyond.