The United States has the largest prison population in the world. But, until the publication of Michelle Alexander’s book “The New Jim Crow,” in 2010, most people didn’t use the term “mass incarceration,” or consider the practice a social-justice issue. Alexander argued that the increasing imprisonment of Black and brown men—through rising arrest rates and longer sentences—was not merely a response to crime but a system of racial control. “The drug war was in part a politically motivated strategy, a backlash to the civil-rights movement, but it was also a reflection of conscious and unconscious biases fuelled by media portrayals of drug users,” Alexander tells David Remnick. “Those racial stereotypes were resonant of the same stereotypes of slaves and folks during the Jim Crow era.” Plus, a conversation with Reginald Dwayne Betts, who discovered poetry while in solitary confinement, during a prison sentence for a carjacking that he committed when he was sixteen. Betts reads a poem, which appears in his collection “Felon,” about trying to explain to his young son that he has served time in prison.