I have just finished Steve Stoute's book "The Tanning of America; How Hip-hop Created a Culture that Rewrote the Rules of the New Economy". 

If you don't know Steve Stoute, he is a former music artist manager and record executive responsible for launching the careers of a huge number of famous hip-hop and R&B artists, who went on to create Translation, a brand and marketing firm that prides itself on having its finger on the pulse of culture. Translation has gone on to developed a lot of iconic campaigns - think the Justin Timberlake / McDonald's "I'm Lovin' It" partnership.

In essence, the book outlines a history of the rise of hip-hop, and how it has achieved a global connection unlike any other force in a process dubbed "tanning". From Steve:

"But the tale I'm here to tell is less about the music itself and more about the atomic reaction it created, a catalytic force majeure that went beyond musical boundaries and into the psyche of young America - blurring cultural and demographic lines so permanently that it laid the foundation for  transformation I have dubbed "tanning". Hip-hop had come in a time, in places, and through multiple, innovative means that enabled it to level the playing field like no other movement of pop culture, allowing for a cultural exchange between all comers, groups of kids who were black, white, Hispanic, Asian, you name it. Somehow the homegrown music resonated across racial and socioeconomic lines and provided a cultural connection based on common experiences and values, and in turn revealed a generationally shared mental complexion."