Talk to anyone who lived in New York City in the 1970s, and they will probably highlight the city’s widespread crime. Times Square wasn’t yet Disney-fied and Brooklyn hadn’t been taken over by hipsters. Most people agreed that New York was a dangerous place. But then something happened: murders, and violent crime in general, began to drop. And that trend wasn’t unique to New York: It happened in many places across America. So who do we have to thank for the crime decline? To find out, we talk with NYU sociology professor Patrick Sharkey about his book, “Uneasy Peace: The Great Crime Decline, the Renewal of City Life, and the Next War on Violence.”