It's the shortest of the books so far, and a less systematic treatment. The writing is lovely, as usual, but I'm afraid my impression of the book was a little hampered by my feeling that maybe she's a religious relativist...what I've called the great heresy of our time.
Tickle does have her finger on something, though, as in her rich description of the existential meaninglessness of the modern secular person:
[The] shift from divinity or divine machinations to physical cause-and-effect as the source of our destructive and flawed natures has had an even more demeaning, and sometimes flagrantly neurotic, consequence over the last century and a half. It has robbed Western citizenry, to some greater or lesser extent, of the energizing and focusing dignity of spiritual struggle by robbing us of faith in the eventual benevolence of how things are.
Now our "destructive and flawed" condition is certainly our fault and has nothing to do with God, but the point is well-taken nonetheless, and it says a lot about the spiritual condition of our late modern world.