In recent years, RapGenius has been the go-to website to decipher your favorite Rap lyrics, but it often works best when the artists themselves log on to give their insight. Artists who have created verified accounts to do this include Nas, Kendrick Lamar, GZA, Common, Joey Bada$$, and many more, but now a producer with one of the biggest bodies of work in all of music has joined them.

Mega-producer Rick Rubin recently logged on and added some annotations to some of his classic songs over the past 30 years. He mostly gives insight to the production and recording process, but also touches on the recording artists’ thought process. He gave annotations on how the beat was made and how Jay-Z came up with his verses on “99 Problems“, the aggressive sound on LL Cool J’s “Rock The Bells“, the writing process on Beastie Boys’ “Girls“, and the last-minute mixing and mastering on Kanye West’s newest hit “Only One“.

He makes some interesting points, including how Jay-Z actually wrote down a verse on his laptop when he’s known to form verses in his head without writing, and how Beastie Boys’ “Girls” was written with the music from Isley Brothers’ “Shout” in mind. He also goes into detail about what it’s like working with Kanye West, mentioning engineers scrambling to come up with the best mix for a song and to get it mastered just hours before the deadline. One of his annotations on “Only One” reads: “That’s how it works in Kanye [West’s] world. It used to really give me anxiety, but now I just know that’s what it is. That’s how he likes to work.”

Rick Rubin has had his hand in a lot of music over the past 30 years between his work with Def Jam Records, [Def] American Recordings and Columbia Records, so there are a lot of songs in different genres that he’s annotated. Some other artists he has worked with include Run-DMC, Aerosmith, Public Enemy, Red Hot Chili Peppers, Metallica, Linkin Park, System of a Down, Johny Cash and Eminem. You can find all of his annotations by following his verified Genius profile here.

Related: Rick Rubin Returns to the Dorm Room Where Def Jam Was Founded for the First Time in 30 Years (Video)