restful routes, deciding nesting/session

I am running edge and am torn on whether to use the nesting of 1.) /
users/1/books or 2.) /books (and assume current_user). Also, #1
allows for /books (without a current user) where #2 does not.

#1 avoids the current_user restriction (i could log in as an admin and
not have to switch to a user's session to edit things, etc), #2 looks

Does anyone have any suggestions or know of anything recent (written
on close to whats in edge now) that covers this?

Also, if anyone can elaborate on the best-practices of using a
controller in multiple roles as I hinted at above (/books - no
current_user, and /users/1/books) that would be great. I haven't found
a good example that shows how one action can behave differently
depending on the nesting.