The vast majority of insect species are solitary; only a relatively few orders of ants, bees and wasps are truly ""eusocial,"" living in colonies with only one or a few reproductive females (ensuring all members are related) and workers who collaborate in complex behaviors choreographed by chemical signaling, situational cues and ""dances."" Following up their Pulitzer-winning tome The Ants, science professors Hölldobler and Wilson propose that, at their most sophisticated, eusocial colonies function in ways analogous to the cells of a single large organism (e.g., a vertebrate), which they term the ""Superorganism."" Hölldobler and Wilson's investigation has surprising implications for all types of social animals, including humans, as well as for ""thinking machines"" that use decision-making algorithms. While evolution by natural selection is easy to describe (environment acting on random genetic variations to change biological characteristics), the authors manage the very difficult task of mapping its progress, precisely defining both the sequence of genetic changes and the environmental pressures involved. Formidable but rewarding, this study covers mathematical analysis as well as field data, but in a straightforward manner that guides readers from one remarkable fact or concept to the next, inspiring wonder at the origin of our own societies. 110 color and 100 b&w illus.