Please, if you've requested a book internationally, be patient.
Most of us who ship internatinally necessarily send books by the cheapest possible rate, which is therefore much slower than airmail. Just because you haven't received a book a week after it was sent doesn't mean that the book wasn't sent or that it's lost in the post, and it's not necessary to nag the sender for proof of despatch either.
I've just happily marked as received three books that were sent to me from Malaysia, posted in September 2011. They've taken almost nine months to make the journey to France, but they're here now.