Getting right up there with Steppenwolf's "Born To Be Wild," "No Sleep Till Brooklyn" is one of the greatest road-trip songs of all time. The liner notes of the Beastie Boys' 1986 Def Jam release Licensed to Ill thanks a certain man for his "frozen metal and lead guitar:" the heavy metal guitar riffs that power the song were provided courtesy of Slayer guitarist Kerry King.

Having been a metal fan for years, Rick Rubin was the person who approached Kerry King and convinced him to provide some guest guitar work on the album. One has to realize that at this point in rock history metal's popularity was at an all time high. King, who had been founding force behind Slayer, had already released four albums prior to his cameo in the "No Sleep Till Brooklyn" music video, which was a satirical look at the heavy metal lifestyle. At the time, Slayer fans questioned Kerry's motivation for working on with what was obviously going to be a rap album. Rap and hard rock were still very separate entities and people from either camp often looked disdainfully at the opposing other.

The project came off without a hitch, and soon metal fans as well as hip-hop heads were equally enjoying the rhymes and riffs of Licensed to Ill.Although much of the credit has always been given to Run DMC and Aerosmith's collaboration on "Walk This Way," a person only needs to take one listen Licensed to Ill to see what influenced today's popular "goatee-metal-rap" scene. Rick Rubin's metal-rap hypothesis not only proved to be successful in the late 1980s, but it also still holds true today. Rubin and King would later reunite to work on Slayer's further releases; however, it will be the memorable power chords that Beastie Boys fans will always remember the duo for.

Even though the popularity of heavy metal faded with the advent of the Seattle grunge movement of the early 1990s, King's band Slayer continued to put out album after album. Most recently, King has released the Hatebreed album appropriately entitled Perseverance (2002). Now that hip-hop reigns supreme as the world's most controversial division of popular music, it is ironic that one of rap's most well known anthems would not be the same if it weren't for the contribution of a heavy metal guitarist.