<b>Now available in paperback from psychologist and award- winningcolumnistSusanPinker, the groundbreaking and contro- versial book that is “lively, well- written...important and timely” (<I>The Washington Post</i>).<P></b><P>In   this   “ringing   salvo in the sex-difference   wars” (<I>The New York Times Book</i> <I>Review</i>),  Pinker  examines  how<I> </i>fundamental sex differences play out over the life span. By comparing   fragile   boys   who succeed  later  in  life  with  high- achieving   women   who   opt out  or  plateau  in  their  careers,<P>Pinker turns several assumptions upside down: that women and men are biologically equivalent, that intelligence is all it takes to succeed, and that women are just versions of men, with identical interests and goals. In lively prose, Pinker guides readers through the latest findings in neuro- science and economics while addressing these questions: Are males the more fragile sex? Which sex is the happiest at work? Why do some male<P>college dropouts earn more than the bright girls who sat beside them in third grade? The answers to these questions are the opposite of what we expect.<P>A provocative and illuminating examination of how and why learning and behavioral gaps in the nursery are reversed in the boardroom, this fascinat- ing book reveals how sex differ- ences influence career choices and ambition. Through the stories of real men and women, science, and examples from popular culture, Susan Pinker takes a new look at the differences between women and men.