Developing a collection is vital to any library. Here is a list of some of the basic books that you should consider for a religion collection. They will not contain highly specialized books. The focus of these books is a good overview or introduction to a topic. For your convenience author's names are linked to their location at Amazon.com.

Merriam-Webster's Encyclopedia of World Religions, by Wendy Doniger (Editor).
The essential, one-volume, encyclopedia of religions. It is clear and non-judgmental.

Atlas of the World's Religions, by Ninian Smart (Editor) and Ailsa Heritage (Editor).
"This superbly illustrated and organized reference source is the first comprehensive visual guide to the world's religious traditions. With text by leading experts, and lavishly illustrated with photographs, thematic maps, site reconstructions, and tables and charts, many in full color, the Atlas charts the origin, growth, and spread of all major faiths."

The Facts on File Encyclopedia of World Mythology and Legend, by Anthony S. Mercatante.
A comprehensive listing and explanation of the various gods and goddess of mythology, as well as important figures of various world religions.

The Encyclopedia of Eastern Philosophy and Religion: Buddhism, Hinduism, Taoism, Zen, by Ingrid Fischer-Schreiber, Franz-Karl Ehrhard, and Kurt Friedrichs.
"Dharma, karma, yoga, Tao--what does it all mean? Buddha, Krishna, Lao-tzu, Rinzai--who in the heck were they?"

The Anchor Bible Dictionary (6 Volume Set), by David Noel Freedman (Editor).
"Six years in the making, this state-of-the-art dictionary offers the most up-to-date and comprehensive treatment of biblical subjects and scholarship. An essential reference for every serious reader of the Bible."

Butlers Lives of the Saints, by Paul Burns (Editor), Peter Doyle (Editor), and Alban Butler.
This is the series on the lives of Catholic saints. Purchase the four volume set for a more complete listing of saints.

The Concise Encyclopedia of Islam, by Cyril Glasse and Huston Smith.
An insightful work covering the Islamic world and cultures. An essential resource for understanding the past and present influence of Islam.

Jewish Literacy: The Most Important Things to Know About the Jewish Religion, Its People and Its History, byJoseph Telushkin.
A reference book that encompasses religion and culture, yet is never dry and dull. A gem.

The Encyclopedia of Witches and Witchcraft, by Rosemary Ellen Guiley.
"Some 400 entries survey the topic from its early pagan heritage to the present. Special emphasis is placed on the periods of witch persecutions, including the Inquisition and the Salem trials of 1692. Black and white illustrations."