Second, I have always found manners books absorbing and have read all of any age that crossed my path. Like most rules, manners are written from social heights. Many decrees for how (or how not) to do things — to use snail tongs and fish knives, finger bowls and consommé cups and other formalities of fine dining — seem built to keep interlopers out, as part of what Charles William Day, in “Hints on Etiquette and the Usages of Society” (1834), calls “the barrier which society draws around itself as a protection.” Some standards change, like passwords, as soon as they’re no longer secret. Forks had to be switched from left to right hand, until everyone was doing it, and then they had to be held fast in the left one. (Europe went along with the change; the New World, in a streak of rebellion, didn’t.) Hands must be on the table . . . or must be off. Asparagus is finger food until it is fork food. Many of the guidelines are anodyne; but any populist would be justified, scanning the lot, in seeing a system for social segregation, and declaring that none of it matters — and that books on etiquette are useful only to prop up the legs of the kitchen table.