The Encyclopedia of World Religion
By Robert S. Ellwood, General Editor, and Gregory D. Alles, Associate Editor
Facts on File, 2007
This reference volume, intended mainly for middle and high school students but accessible to all, should provide answers for innumerable basic questions people have about religion: What does this one believe; what is the meaning of that deity, practice, or technical term; how is such-and-such a church or group organized? Entries range from Aaron to Zoroastrianism, and those on major religions or denominations are divided into subsections on History, Belief, Practice, and Organization. Let me know if you find it useful.