J Dilla (aka Jay Dee) and Madlib are Jaylib. The steps toward a collaboration began in 2000 when LA based DJ J Rocc gave Madlib a CD of Dilla beats to listen to. Madlib was so inspired that he recorded a whole album in his Bomb Shelter Studio, rapping over them for his own ears only and for lack of a title, scawled "Jaylib" across the CDR in a black Sharpie.
Madlib and Dilla briefly worked together in 2001 for Dilla's MCA album which was never to be released. But the real course towards the "Jaylib" collaboration began when a bit of extra space popped up on white label wax that Stones Throw Records' honcho Peanut Butter Wolf was preparing for a mix tape. For this, he was quick to grab a track from the Jaylib CDR that was never to see commercial pressing, "The Message" - Madlib's flip of the hip hop classic over J Dilla's beat. Only 300 records were pressed, but the track credited to Jaylib was clearly a hit.
Wolf soon recieved a suprise phone call from J Dilla himself, who heard the track and declared, “Hey, I want to do some s**t like that!" Wolf proposed doing a single or EP and Dilla replied, “Why not record an entire album?” Wolf and Dilla casually brainstormed and decided that half of the album could feature Madlib rhyming over Dilla’s production & the other half could be vice versa. Beat tapes were floated between Detroit and Los Angeles and months later, the album was born.