From the very start applicants had to comply with stringent regulations, the purpose of which was, and still is , to give purchasers guarantees of quality.
Similar organisations exist in numerous other countries.
Members of the NVvA are thus part of an international network of dealers who, thanks to their expertise and to the rules of behaviour imposed by their associations, form the best contacts for collectors of old books and prints. More specially in the case of large financial transactions, their guarantees of authenticity, completeness, and condition, with the right to return any goods for defects not mentioned and total repayment, are a security which no purchaser would want to do without. In the case of a sale of complete collections, or of a few valuable items, members of the association are well informed of the international market and of the best possibilities for dividing or combining lots, guaranteeing the vendors best results and prompt payment. Members of the association can also be of assistance in tracing books or prints considered difficult to find. Some members have a special search service, by means of which the would-be purchaser gains access to stocks spread all over the world.