1: The VAT rate on books is 6%, and 19% on prints and maps.
2: Within the EU, all sales are liable to VAT, except when the buyer has a VAT number (such as businesses and a number of institutions).
3: Within the Netherlands, all sales are subject to 6% VAT, regardless whether the buyer has a VAT number or not. When the buyer has a VAT number, he gets the VAT refunded from the Finance Ministry.
4: Some Dutch dealers show prices inclusive of VAT, others don’t. There is an EU regulation which allows to have the VAT included in the price, in which case, the VAT is calculated on the profit margin (hence the label 'Margin Regulation') of the sale. This is only allowed if the book has been bought from a private person, and each object thus bought must be individually traceable through one’s records. If one chooses this option VAT is included in the price and may not be shown or mentioned on the invoice. In this case a buyer from outside the EU has to pay the VAT as well and has no way of reclaiming it.
This EU regulation is a choice: even when one buys from private persons one may choose to have a price and add the 6% VAT over the full price, so that it can be deducted (or not added) if sales are made outside the EU or within the EU to buyers with a VAT number.
5: When sales are made outside the EU, VAT is not charged. Dealers should be able to prove that sales are made outside the EU but everybody understands that that is sometimes difficult: lawyers have pointed out that receiving a cheque from the Library of Congress still does not prove that a book was actually shipped to the Library of Congress. Hence there exists a compromise: if a payment is received from outside the EU and the financial administration of the dealer is found to be impeccable, the tax department will accept that as proof of sale outside the EU.
Obviously: if prices include VAT it should be deducted when such a sale is made.
6: When books are imported from outside the EU, VAT is paid at the border, but very often books arrive as a small parcel without them having been controlled, and without them having been charged. If a dealer gets charged he can reclaim the VAT.