The word "Islam" means "submission." One may ask submission to what or whom? A Muslim is a person who is obedient to the will of "Allah." According to the words of the Prophet of Islam, Allah is the author of the holy book of Quran, thus a Muslim is a person who must do what the book says to do. If he or she does not follow the words of the Quran, then he or she is not considered to be a Muslim