Perhaps no other Western writer has more deeply probed the bitter struggle in the Muslim world between the forces of religion and law and those of violence and lawlessness as Noah Feldman. His scholarship has defined the stakes in the Middle East today. Now, in this incisive book, Feldman tells the story behind the increasingly popular call for the establishment of the shari'a--the law of the traditional Islamic state--in the modern Muslim world.

Western powers call it a threat to democracy. Islamist movements are winning elections on it. Terrorists use it to justify their...