So I got my first damaged book today.  I know to mark it received with a problem, but when it asks "damaged by sender" or "damaged by usps," I'm really not sure what to check.

The envelope it was sent in was intact upon receipt.  About 3 inches of the book's spine is crushed.  The member could have sent it that way or it could have been damaged during shipping.  What do I do, oh wise ones?

Can you see damage on the envelope it came it?  I got one book nicely wrapped in the PBS wrapper and it looked like the USPS tried to fold the book in thirds.  I could tell it wasn't sent that way because the creases on the wrapper matched the creases on the book.

If the book was damaged enough by the USPS to crush the spine of it, you should see damage on the envelope unless it's one of those slick plain tyvek ones.