When I started collecting Queen Wilhelmina I soon found that I needed a catalogue with all the postal stationery in. The word "Geuzendam" kept jumping in my face, as that was apparently the bible for postal stationery collectors. That word was usually spoken in combination with "a new edition will be out soon", but that proved to be a long soon. A new edition has been more than 10 years in the making, and in all those years I've never been able to get hold of a copy of the old edition.
So you can imagine how happy I was to find out just before Christmas that the new edition is finally here among us! I ordered it earlier this month but I shall have to wait another long period, for I had it sent to my parents' house in Holland to save postage! I can't wait!
I really do think, though, that postal stationery should be part of any stamp catalogue, or at least of the specialized ones, as they form an interesting part of the many definitive sets. There's plenty of interest in them judging from the various stamp magazines. So take heed, catalogue editors!