The June 14 issue of The New Yorker, perhaps the premier showcase for American fiction, features a list of “20 Under 40” — that is, 20 accomplished writers under the age of 40. Many of the names are familiar: Joshua Ferris, Jonathan Safran Foer, Nell Freudenberger, Rivka Galchen, Nicole Krauss, Gary Shteyngart, ZZ Packer, Wells Tower.