Ava DuVernay, director of the Oscar-nominated film Selma, released 13th on Netflix earlier this month. The acclaimed documentary explores the staggeringly high rates of incarceration of black Americans in the United States and traces the issue from its roots in American slavery through to the present day. After the release of 13th, Complex sent rapper Pusha T, ​an increasingly outspoken advocate for criminal justice reform, to talk to DuVernay about her film and the racist history behind America's prison problem.