Thackeray uses one of the oldest tricks in the book: the compare-and-contrast pair of main characters. (How old is this setup? Really old. Think Martha and Mary in the New Testament or Achilles and Hector in The Iliad.) Becky is blonde, whip-smart, sexy, driven, and immoral. Amelia is brunette, quiet, pretty, passive, and old-school. Really, the only thing they have in common is their age and gender, which makes them excellent foils for each other. Set them loose in the world, says the novel, and decide who you think will come out on top.