From

1. Dunbar’s Number: the number establishing the limit on meaningful relationships one person can maintain. In showing how this number reflects the biological history of humans as distinctively social primates, Dunbar illustrates how recent advances in evolutionary science have enlarged the explanatory power of the Darwinian paradigm. Within this increasingly potent paradigm, readers learn, for example, why societies experiencing birth ratios unfavorable to females face serious crime surges in the decades ahead and why tall politicians (e.g., Obama) enjoy a pronounced advantage over short rivals (McCain). Dunbar’s work, of course, connects with the sociobiological theories advanced by E. O.Wilson in the 1980s, leaving some readers with the same questions about the potentially reductive implications of an overly biological framework. Does the distinctively human impulse to worship, for instance, manifest only the way that ritual behavior biochemically fosters group cohesion among anthropoids? Some readers may indeed wonder if Dunbar might not use his science more plausibly if he shared with biologist Peter Medawar an appreciation for its limits. Still, this is lucid and provocative. --Bryce Christensen

Review

An eclectic collection of essays on humanity and evolution with something for everyone. Dunbar explains, among other things, why monogamists need big brains, why it is worth buying a new suit for an interview, how to interpret an advert in a lonely hearts column, the perils of messing with evolution and, of course, how many friends one person needs (150 as it happens, aka "Dunbar's number"). He speaks with authority and seduces us as only a master storyteller can.
--Kate Douglas, New Scientist (20101101)

Lucid and provocative.
--Bryce Christensen (_Booklist_ )