Junot Diaz had writer’s block something fierce as he tried for 11 years to finish his first novel, The Brief Wondrous Life of Oscar Wao. But now the pressure’s off for the Dominican-born MIT writing professor. The novel, published in September by Riverhead Books, is widely considered one of the best works of fiction from 2007. And Diaz, 39, says the accolades have him “shell-shocked.” “It’s fun,” he says. “I’m just astonished.”