The most important rap star around today, Kanye West, is a huge fan of Robert Greene's books and has even referenced his book The 48 Laws of Power in one of his songs.

Greene is seen as something of a guru for today's rappers - so much so that he's soon to produce a documentary about how The 48 Laws of Power has had such a big influence in the rap world.

"I think they understand what I'm saying and they like the message I put across," says Greene of his elevated standing in the rap world. "I've been referenced to in lyrics by rappers such as Nas and Ice Cube - it's thrilling for a nerdy white guy like me. I got a phone call a while back from 50 Cent asking if he could meet me. I went to lunch with him and his posse. He told me he's writing a book about the business aspect of rap music and he has asked me to write the preface. I think they enjoy the books because so many rap lyrics are about battles, wars and strategies."