He writes all of his own songs and delights in rhyming words others can't.
We talked to him about how he does it in his private recording studio.
Eminem has said he bends the words.
"It's just in the enunciation of it," he explained. "Like, people say that the word 'orange' doesn't rhyme with anything and that kind 'a pisses me off because I can think of a lot of things that rhyme with orange."
"What rhymes with orange? I can't think of anything," Cooper remarked.
"If you're taking the word at face value and you just say orange, nothing is going to rhyme with it exactly. If you enunciate it and you make it like more than one syllable? Orange, you could say like, 'I put my orange four-inch door hinge in storage and ate porridge with George.' So, you just have to figure out the science to breakin' down words," he replied.
"Do you think about this throughout the day? I mean, you're driving along. Do you think about rhyming words?" Cooper asked.
"Yeah. All day. Yeah, I actually drive myself insane with it," Eminem said.
"But it's interesting. I mean, for a guy who hated school, who, you know, was in the ninth grade three times you spend all your times thinking about words," Cooper remarked.
"I found that no matter how bad I was at school, like, and no matter how low my grades might have been at sometimes, I always was good at English," Eminem said.
"I heard that you used to read the dictionary," Cooper remarked.
"I just felt like I wanna be able to have all of these words at my disposal, in my vocabulary at all times whenever I need to pull 'em out. You know, somewhere, they'll be stored, like, locked away," Eminem replied.
His words are stored but they're not exactly locked away: he actually keeps them in boxes.
Inside are hundreds of scraps of paper on which he's obsessively scrawled down words and phrases.
"So wait, this is a pad from a hotel in Paris it looks like?" Cooper said, looking at some of the papers in one of the boxes. "You just scribbled, you have four little words just scribbled down. How do you even read this? This is tiny."
"I know what it says, I guess. I might use it actually. It's not bad," Eminem replied.
They're not lyrics really - they're just ideas that he collects. He calls it "stacking ammo."
"I've gotten letters from crazy people and they kind of look like this," Cooper said. "Sometimes all in capital letters or scrawled on the page like this."
"Yeah? Well that's probably because I'm crazy," Eminem replied with a smirk.