Islam: What The West Needs To Know discusses the definition and use of violence in the Koran. One of the fundamentals within Islam is called; Nasikh or al-Nasikh wal-Mansoukh."al-Nasikh wal-Mansoukh" (the Abrogator and the Abrogated) means that in situations where verses contradict one another, the early verses are overridden by the later verses. The chronological timing in which a verse was written determines its authority to establish policies within Islam.
It is purported that the Quranic verses that promote equality, peace and justice are more often than not overridden/nullified by later verses that validate such things as murder, terrorism and legalistic restrictions on routine human and women's rights.
This movie explains much of the existing doctrines.