Terry Gross

The plot shakeups at the beginning of this season's Mad Men have left Jon Hamm's character Don Draper a broken man. Hamm talks about Draper's evolution, details how he auditioned for the role and talks about his newest movie, Ben Affleck's crime thriller The Town.

There are 10 times more microbial cells on and in our bodies than there are human cells. And these bacteria aren't just there for the ride. Dr. Jeffrey Gordon explains how they contribute to the physiology of the human body and why they may hold the key to fighting some diseases.

Many of Spencer's novels feature a turning point -- a dreadful, unplanned act committed by one of the characters. In his latest book, Man in the Woods, a carpenter accidentally kills a man, which leads him to question himself and his relationship with God.