Space flight, not what's out there, is the subject of Asimov's latest historically ordered explanation, which begins with the story of Daedalus and proceeds rapidly to the Montgolfiers (who, noting that hot air rose, built the first balloons) and the Wrights (who first put a powered motor on a glider). Such general earmarks are followed, as technology marches on, by more basic but just as easy presentations of the problems involved: How can you make something move through a vacuum? How can you throw a ball so hard it doesn't fall back? How can you avoid being crushed by the velocity required for the escape? The rocket principle is explained via an analogy to balls being thrown off a platter that is sliding on ice--and then it's pretty much back to a non-technical history, skimming through Goddard, Von Braun, and the US-Soviet competition which has resulted in the satellites, probes, manned flights, and Skylab that are finally helping us to find out about outer space. An often sketched chronology, painlessly retraced.