The book I read 'first' for the challenge was:
http://www.goodreads.com/book/show/1461805.Altars_Icons
"Altars and Icons: Sacred Spaces in everyday life"
by Jean McMann
It was about how people instinctively create sacred spaces, very like an Altar or a Shrine- pretty much everyone does it. Ya know?
The book profiles spaces with a picture and the person's explaination of the peices and/or space entirely... what it means to them, why they started it, how they use it or if they simply display it... a HUGE range a things, from genuinely religous or spiritual to completely non-religous.
I think the best part about it was that it explored that human urge to build 'shrines'... little spaces we manipulate to our own pleasure, no matter WHY. Having the people be the ones to explain it was really facinating.
I think this would be a great book for anyone contemplating paganism or priest(ess)hood, because it touches on some very intimate things in a very soft, almost casual way. Very thought provoking. :)