About 25 years ago, ad men Steve “Steinski” Stein and Douglas “Double Dee” DiFranco crammed two dozen records into “The Payoff Mix,” a hip-hop classic that folks are still mining breaks from. This long-overdue retrospective, What Does It All Mean?, shows that Stein never lost his game. Among the essentials are the “Lesson” mixes (pitch-perfect snatches of old-school rap, funk, and cartoon wisecracks) and Stein’s controversial hip-hop piece on the JFK assassination, “The Motorcade Sped On,” alongside a clever anti-Gulf War protest, “It’s Up to You.” As well, the lesser-known “Vox Apostolica” and “Everything’s Disappeared” are great, scratched-up examples of hip-hop gone mental. Grab this and get schooled by the master.