The rapper who completely reinvented the form on his own.
Let's begin here, a place that seems furthest away from the universe of "The R" (as the veteran rapper Rakim often called himself): Back in the 1960s, the American anthropologist Loren Eiseley famously and poetically wrote that flowers dramatically changed the appearance of the earth 100 million years ago. Before this flower revolution, the earth was dull and monochromatic; after the flowers, there was color everywhere. Eiseley wrote, "A little while ago—about one hundred million years, as the geologist estimates in the history of our four-billion-year-old planet—flowers were not to be found anywhere on the five continents. Wherever one might have looked, from the poles to the equator, one would have seen only the cold dark monotonous green of a world whose plant life possessed no other color. Somewhere, just a short time before the close of the Age of Reptiles, there occurred a soundless, violent explosion. It lasted millions of years, but it was an explosion, nevertheless. It marked the emergence of the angiosperms—the flowering plants. Flowers changed the face of the planet."
I mention this because it comes close to how I see Rakim's impact on the world of rap. Before he came onto the scene in the mid 1980s, rap was very simple and stiff—basically no better than Mother Goose rhymes. True, there was the urban realism of Grandmaster Flash and the Furious Five's "The Message," and even the futurism of T La Rock's "It's Yours" (Def Jam's first single). But as a whole, there were only two types of rappers: good wack rappers and bad wack rappers. Roxanne Shanté was, for example, good wack; the Real Roxanne was bad wack. In short, nothing was not wack. After Rakim released five groundbreaking hiphop tracks in 1986 and 1987 (in this order: "Eric B. Is President," "I Ain't No Joke," "I Know You Got Soul," "Move the Crowd," and "Paid in Full"), something was finally separated from the monochromatic wack. And for the first time, we could see rhymes in living color. (A quick note: The Beastie Boys were a part of the wack rap moment in hiphop—though of the good variety—and never really parted with it, but preserved it, even to this day, like a kind of fossil. One more note: Listen to "Down with the King" and you will hear the difference between rap's pre-Rakim moment [Run-D.M.C.'s section] and post-Rakim moment [Pete Rock and CL Smooth's section].)