Shia Muslims account for between 10 and 15 percent of the world's Muslim population, and while some Americans know that there are two major sects in Islam, Shia and Sunni, not many of those know the differences between the two traditions. Further compounding the problem is the fact that those few who are aware of the dissimilarities almost always acquire their knowledge of Islam from a Sunni perspective. The result is that a rich and important...