O'Connor's "Theology" is a two-disc set whose songs are culled from mostly Old Testament passages.
"They're very emotional -- particularly the Old Testament is very emotional," said O'Connor, who is an ordained minister in the Independent Catholic sect and has often commented on religion in her music and interviews.
"What I love is the God character in the Old Testament is a very human type of character -- crying one minute, angry the next, sorry he was angry the next ... So it's very dramatic. It appeals to an artist from that point of view."
"Theology" also includes a cover of "I Don't Know How to Love Him" from the musical "Jesus Christ Superstar."