War Music is a mixtape by American rapper Slim the Mobster, hosted by DJ Whoo Kid. The album is Slim's debut on Aftermath Entertainment with Gang Module, released on November 9, 2011. It was originally due out on the 25 October. On 7 November, Slim confirmed it had been pushed back an extra day so that Dr. Dre could finish mastering the song he featured on. Guest features include Dr. Dre, Snoop Dogg, Kendrick Lamar, Prodigy of Mobb Deep, Yummy Bingham, Nikki Grier, Sly, and D. Brown. Production was handled by Dr. Dre, Jake One, Sha Money XL, Bink!, Boi-1da, Rahki, and others. It was hosted by DJ Whoo Kid, and mastered by Mark B. Christensen.
Slim released the singles and accompanying videos to "Gun Play" and "Work For It (Price On Ya Head)" onto his official YouTube channel on the 6 September and 20 September. Followed by the upload of Doom Freestyle. He later released "What Goes Up" onto his official Facebook page on October 5. DJ Whoo Kid previewed the Dr. Dre featured track "Back Against The Wall" on Shade 45 on 6 November.