At a time when computers were a short step removed from mechanical data processors, Licklider was writing treatises on "human-computer symbiosis," "computers as communication devices," and a now not-so-unfamiliar "Intergalactic Network." His ideas became so influential, his passion so contagious, that Waldrop coined him "computing's Johnny Appleseed." In a simultaneously compelling personal narrative and comprehensive historical exposition, Waldrop tells the story of the man who not only instigated the work that led to the internet, but also shifted our understanding of what computers were and could be.