By Thom Geier
Updated April 29, 2009 at 04:00 AM EDT

Benji Cooper, the hero of Colson Whitehead’s autobiographical fourth novel, Sag Harbor, is one of the few blacks at his Manhattan prep school and a Dungeons & Dragons fan. He’s one part Cosby kid, one part Oscar Wao. Like Junot Díaz’s übergeek, Benji has a knack for witty observations about his life — particularly his summers on the East End of Long Island. But while Benji’s voice is compelling, the plot is sand-dollar thin. Whitehead rhapsodizes about familiar teenage high jinks but drops only hints about major conflict in the future (a buddy shot dead in drug-related violence). Nostalgia that doesn’t carry the full weight of hindsight feels a lot like solipsism. B