The booklet is really cool, but not required at all to sail. It does have luggage tags, but even those you can get on the spot from the luggage handlers at the terminal. We like the book because it does have information about our cruise, our dinner and excursion reservations, contact information for friends, and neat information about the ship and the sailing, but we never stress because you absolutely do not need it to show up and sail away.
In fact, all you really need to sail is your proper ID (passport, DL/birth certificate, etc) and a payment method (credit card). It's nice to do final registration online, but not required. It's nice to have the booklet, but not required. There are no cruise "documents" (in an official sense) sent to you ahead of time.
So...don't stress if it hasn't shown up 10 days before your cruise. If you want some reassurance they haven't forgotten you, you can always go online or call them, but your cruise is coming and once onboard all the getting ready worries and stress evaporate into pixie dust.