Since the music industry began, about 1,868 rap music has been the subject of much review of lyrics and the information it depicts. There is a long history in the history of rap songs, from the era of slavery, it has been a long since later to fill the gap between various music types including jazz, blues, basic drums. When hip-hop first appeared, the message was simple. A group of blacks explained their lives in slums around the world.
Rap music is a subset of hip-hop music that has become a controversial genre since the birth of the late 1970s. For many people, rap music is related to obscene words, violent themes, and women's sexuality. Nonetheless, this kind of history and its popularity on a global scale gives it a unique advantage in providing political commentary and resistance to it. Hip hop appeared in a very poor time in southern Bronx. After the civil rights era, the large urban African-American community experienced serious investment and was neglected by the government. Without their own mistakes, urban areas like the Bronx are full of crime, violence, unemployment and substance abuse. The young culture inspired by these difficult times insists their identity and tries to express the struggle for the stranded people. Hip hop is a product of this era, apartheid in the history of the United States.
When N. W. A appeared in the late 1980's, they began gang wraps in a new way of rap. They explain the events and experiences they live in that food, with violence and clear words, Compton. This movement gradually became a commercial music style, and everyone in the world started listening to gangsters who wanted to learn about culture. Over the years, many other wrappers, such as Tupac, Redman, Agate, have adopted this style, but they are degraded somewhat, but are returned in a new format called "trap music".