I would not want to bring any antiquarian books on a long cruise but general books (paperbacks, cruising resources) do fine. If you have a deck or other leak near a book shelf it would not be a good thing but such is life.
Back to Grenada in early December. Not sure I will remember how to sail. Will spend the winter and early spring in the Caribbean and then head to Bermuda and the northeast US. Still trying to decide if we will bring the boat to Canada, either in 2015 or 2016.