Madlib is a legend. Born Otis Jackson, Jr. the producer, rapper and multi-instrumentalist has always retained a sense of mystery about him, even though he's far more accessible than some of his more eccentric collaborators. Like many of the underground luminaries he's often compared to—Dilla, the Alchemist—Madlib has carved out a mercurial and fascinating niche in the world of hip-hop without bowing to trends or pandering to the masses.

In celebration of the producer's 40th birthday today, we've gone ahead and selected 15 beats that show the wide range of his talents. From his earliest collaborations with his group Lootpack to his more recent projects with Freddie Gibbs, Madlib always gives you a reason to turn the volume up. --Dan Jackson And Eric Diep