In “History of Beauty,” Umberto Eco explored the ways in which notions of attractiveness shift from culture to culture and era to era. With ON UGLINESS, a collection of images and written excerpts from ancient times to the present, he asks: Is repulsiveness, too, in the eye of the beholder? And what do we learn about that beholder when we delve into his aversions? Selecting stark visual images of gore, deformity, moral turpitude and malice, and quotations from sources ranging from Plato to radical feminists, Eco unfurls a taxonomy of ugliness. As gross-out contests go, it’s both absorbing and highbrow.