There’s a reason why Eminem is credited as being one of hip-hop’s most prolific lyricists. It’s because he is. Marshall Mathers delivers on every track he approaches—whether it’s his or someone else’s. He has a knack for switching up his style to fit anything he sonically steps into, turning hum-drum tracks into bangers and morphing stand-out songs into classic. He's a formalist at heart, always looking for new ways to wrap his words around a particularly challenging beat. He'll steal a song right from under you if you're not careful.

While we anxiously await Eminem’s upcoming Marshall Mathers LP 2, XXL has compiled some of Em’s best guest verses, from the super mainstream to the more obscure. Truth be told, it’s hard to find the best of the best in the midst of Em’s whole catalog, but we’ve pulled 15. Check them out.

“Forgot About Dre” – Dr. Dre Featuring Eminem
A song dedicated to immortalizing Dr. Dre somehow became a song starring Eminem. From the hook (“Nowadays, everybody wanna talk like they got somethin’ to say…”) to Eminem’s ricocheting verse, on “Forgot About Dre,” Eminem made sure no one would ever forget about Shady.

“Forever” – Drake Featuring Kanye West, Lil Wayne & Eminem
Drake’s posse cut about determination got an extra boost with the help of Em. He surprisingly popped up on this song and closed it out in the best way possible. “I’m Hannibal Lecter, so just in case you’re thinking of saving face. You ain’t gonna have no face to save by the time I’m through with this place.” And there you have it.

“Don’t Approach Me” – Xzibit Featuring Eminem
Eminem is pretty passionate about not being bothered by the greater public. He’s mentioned it on a few tracks, and here he and Xzibit both channel their celebrity woes into the song. Em takes it to the next level though by suggesting he pumps some folks full of lead (X does too, but only the wealthy. Oh wait.).

“We All Die One Day” – Obie Trice Featuring 50 Cent, Eminem & Lloyd Banks
Everybody does pretty well on this song, but Eminem wins at life with this line: “I’m a pyscho, Mariah ain’t got shit on me.” That’s clearly a dropping the mic and walking away line.

“Renegade” – Jay Z Featuring Eminem
The truth about this song is that “Renegade” was originally a Royce Da 5’9 and Eminem track – aka a Bad Meets Evil song. However, once Jay Z inherited the song, and Em became a feature, it was clear Marshall was more comfortable around the beat. His bars proved it.

“Patiently Waiting” – 50 Cent Featuring Eminem
The idea of discussing 9/11 was and still is sometimes taboo. Eminem didn’t seem to care with his bars about Shady Records being “80 seconds away from the towers,” suggesting that his label was the one aiming to get hit by terrorists. Bold words, Mr. Mathers.

“What’s The Difference” – Dr. Dre Featuring Xzibit & Eminem
The beauty behind Eminem’s bars on this track is that while Dr. Dre and Xzibit adopt this Cali chill yet rugged approach to the track, Eminem jumps in and turns it on its ear. Isn’t that his job though?

“The Last Hit” – High & Mighty Featuring Eminem
Those not familiar with the High & Mighty will find that their hyper-lyrical approach to rap might be difficult to compete with once you’ve been baptized by the mainstream. Eminem reminds heads how he came from the battleground on this. Don’t underestimate the eternal skills.

“Roman’s Revenge” – Nicki Minaj Featuring Eminem
We don’t know if this song is really about Lil’ Kim (yeah, right), but Eminem took every opportunity to join in the shit-talking. “I ain’t into S&M, but my whip’s off the chain,” opens Em with the triple entendre. Let’s not forget that he makes a human tripod on the track too.

“Drop The World” – Lil Wayne Featuring Eminem
While the pairing of Lil Wayne and Eminem might seem like an ungodly combination, on a track like “Drop The World,” it’s very necessary. Weezy is busy hopping in his spaceship while Eminem details an emotional apocalypse. There’s a balance to that. Sort of.

“Welcome To D-Block” – Jadakiss Featuring Eminem, Sheek Louch & Styles P
“Welcome to D-Block, the mighty mighty D-Block. The place in New York City where Diddy won’t even walk. It’s D-Block, the part of Yonkers I wouldn’t be caught.” Eminem does not even care. He’ll throw a jab at Puffy and then turn around and make fun of himself. Genius.

“Don’t Push Me” – 50 Cent Featuring Eminem & Lloyd Banks
Em’s bars on 50 Cent’s track are actually pretty vulnerable, considering he could’ve been running his mouth to change up the whole tone on the song. He chose to continue along the same vein as his co-collaborators and in doing so helped create a pretty poignant track.

“Dead Wrong (Remix)” – Notorious B.I.G. Featuring Eminem
Jumping on a legend’s track years after he passed away is a difficult task, but Em was up for the challenge. Besides, he re-produced the posthumous track “Runnin” with Biggie and Tupac, so jumping on a cut was inevitable, and he did it proper justice.

“Airplanes Pt. II” – B.o.B. Featuring Hayley Williams & Eminem
Truth be told, the pop community embraced “Airplanes” way more than the hip-hop community ever did. However, throwing Eminem into the mix on “Pt. II” provided a much needed grittier perspective for B.o.B.’s crossover single.

“Busa Rhymes” – Missy Elliott Featuring Eminem
Okay, let’s be honest here. This song is technically Missy’s, but we can all agree it’s Eminem’s by default right? Besides, anyone who opens up someone else’s track with “Well I do pop pills, I keep my tube socks filled. And pop the same shit that got Tupac killed” is basically saying “I can take it from here.”

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