Poets have written about it, songwriters sung about it, but what do scientists say about the intimate process of boy meets girl? Q.E.D. looks at the ways they have been investigating the first magic moments of attraction between the sexes. What's the primary thing we look for in the opposite sex? Are men and women attracted differently? How far do personality differences affect our choices? Why are men and women's bodies so unalike? What's the best opening gambit? And might we be turned on by people's smell? All this and more in a dispassionate appraisal of our more passionate feelings.