To no one’s surprise, Jonathan Franzen’s new novel, Purity, was published this fall to critical acclaim and commercial success. Like his last two novels, Purity features a dysfunctional family. A young woman, Purity “Pip” Tyler, saddled with $130,000 in student debt and a reclusive, emotionally dependent mother, is trying to discover the identity of her father, whom she hopes will help her out. It’s more complicated than that, of course. The novel actually features three dysfunctional families whose fates are implausibly intertwined. Franzen’s tale, as you might expect, is freighted with social commentary.