New York Times best-selling author Adam Mansbach has enlisted the talents of J. Period on a mixtape being created as a companion-piece to his new novel Rage Is Back–and OKP has the exclusive sneak peek! Check out the one and only Black Thought of the Legendary Roots Crew as he freestyles over the Nas classic “N.Y. State of Mind,” showing un-lettered MCs how to kill a damn mockingbird.