Library of Congress call numbers group books by subject, but there is no single call number range for all religious studies materials. The following letters represent major religious studies categories:
BL: Religions. Mythology. Rationalism
BM: Judaism
BP: Islam. Bahaism. Theosophy, etc.
BQ: Buddhism
BR: Christianity
BS: The Bible
BT: Doctrinal Theology
BV: Practical Theology
BX: Christian Denominations