Remember the dreams of the late 20th century? Orbiting solar panels would beam down the planet's power supply. Machines on the moon would grind out raw materials and spit them into space to build space colonies and zero-gravity factories. Everything we wanted would be manufactured molecule by molecule, via contraptions smaller than the smallest objects we previously knew. From our June issue, Senior Editor Brian Doherty reviews historian W. Patrick McCray's The Vioneers: How a Group of Elite Scientists Pursued Space Colonies, Nanotechnologies, and a Limitless Future.