Spiritual sounds

I've listened to Indigo Girls for more than 15 years, and I had no idea (A) that Emily Saliers had a spiritual side, (B) that her father was a church musician and theology professor and (C) that father and daughter collaborated on a book about spirituality in music. Might need to add that to the never-ending stack of stuff I should read if I ever quit spending every night online like Mrs. MMM and I keep saying we will.