From boom bap to EDM, we look at the line between hip-hop and not, and meet a defender of the genre that makes you question... who's in and who's out.

Over the past 40 years, hip hop music has gone from underground phenomenon to global commodity. But as The New Yorker's Andrew Marantz explains, massive commercial success is a tightrope walk for any genre of popular music, and especially one built on authenticity and “realness.”  Hip hop constantly runs the risk of becoming a watered-down imitation of its former self—just, you know, pop music.

Andrew introduces us to Peter Rosenberg, a guy who takes this doomsday scenario very seriously. Peter is a DJ at Hot 97, New York City’s iconic hip hop station, and a vocal booster of what he calls “real” hip hop. But as a Jewish fellow from suburban Maryland, he's also the first to admit that he's an unlikely arbiter for what is and what isn't hip-hop.

With the help of Ali Shaheed Muhammad of A Tribe Called Quest and NPR's Frannie Kelley, we explore the strange ways that hip hop deals with that age-old question: are you in or are you out?

Special thanks to The New Yorker who let us do a radiophonic version of their piece. If you've got a New Yorker subscription check out Andrew Marantz's stellar written version here. If you don't, well you should get one, but you can also watch Rosenberg crate digging and spinning records here.