“The Marriage Plot,’’ by Jeffrey Eugenides (Farrar, Straus & Giroux, 416 pages, $28) Ah, the 80s! Brown University! Semiotics! Eugenides’s first book since Pulitzer-winner “Middlesex’’ mixes Gen-X nostalgia with questions of love, art, and spirituality. Readers follow idealistic, literature-besotted Madeleine into post-college (and post-modern) life, with its inevitable compromises. “Salvage the Bones,’’ by Jesmyn Ward (Bloomsbury, 272 pages, $24) Winner of this year’s National Book Award, Ward’s second book tells of an approaching hurricane, a southern family, and survival in the meanest circumstances. In short, the first great novel about Katrina.