Paul O’Rourke, the narrator of Joshua Ferris’s third novel, is a dentist who spends his days staring into the murky recesses of his patients’ mouths. Despite encouraging them to floss, he is himself a man of curiously ingrained habits. Averse to the digital age and oddly superstitious, he stockpiles VHS recorders and watches the Boston Red Sox with a plate of bland chicken and rice, always careful to avert his eyes from the sixth innings.