I tried today to order some ArM books (Rival Magic and HoH:S) from a retailer. He told me that the books were not available and that he is waiting for a reprint. Similar information was give to me regarding Mystery Cults a while ago.
Now, are these (or other) books sold out? Do they even get reprinted? Or will I have to use pdfs for these, as new print runs might be too expensive ? I do buy pdfs every now and then, but I prefer "dead tree" books to screens.
Amazon says 2 left in stock (get rid of the space after "www," I couldn't remember rules about such links):
www .amazon.com/Houses-Hermes-Societates-Ars-Magica/dp/1589781198/ref=sr_1_3?ie=UTF8&qid=1404910831&sr=8-3&keywords=ars+magica+houses+of+hermes
Also, try Warehouse 23 or some other online sources.
I checked our warehouse and we have a very small amount of ArM: Mystery Cults and ArM: Societates. I have quite a large stock of ArM: Rival Magic. They are currently available to all distributors. As to reprints, it does need to make financial sense to print a book or we wait to get several books that are out of print before ordering their reprints (the more we order, the less expensive the books become). With Ars Magica, reprints are done in paperback versus the original hardcover. The layout becomes different and requires extra work as well. So it can take some time. Ask your retailer to please place a special order for you from their distributor or you can use online bookstores as mentioned in the other reply (Amazon, Warehouse 23, etc)
Thank You,
Travis
Travis,
thanks a lot for your effort, and the information regarding reprinting. I´ll see if I can get some retailer to order the books for me.
I guess I should have mentioned that I´m living in Germany 
, so getting US books is sometimes not as easy as I´d like.
So, I gave the following wish list to my FLGS the other day:
Houses of Hermes: Mystery Cults
The Mysteries, Revised Edition
Art & Academe
Tales of Mythic Europe
Lords of Men
Rival Magic
The Church
Hermetic Projects
Hooks
They asked their retailer. Only the first two were available, the others not in stock. Art & Academe was not even listed.
It could be the retailer not wanting to have too many books in stock that are not sold very often, or are all these sold out?
All of the books in your list other than Art & Academe are currently available from our warehouse. (Art & Academe will be released in a softcover edition soon. You just happen to have emailed in between the hardcover going out of stock and our preparation of a softcover edition.)
If you have contact information for the retailer where you'd like to buy these books, we can get in touch with them and let them know what our stock status is. Alternately, you can put them in touch with us at 651-638-0077, or travis at atlas dash games dot com (that's a direct email to Travis Winter, our warehouse manager). We do have direct-to-retail terms if their distributor can't or won't stock there titles, although it's usually most convenient for everyone to ship books through the regular channels.
As a final alternative, we could sell you the books directly by special order. We don't usually do that, and shipping to Germany might be expensive, but we would like to see you have the books you want.
Thanks for your patience, and sorry about the inconvenience!
Jeff,
thanks a lot for your information and looking into that. I guess distributors over here just don´t want to stock the books all that much, as they are probably not a top-seller. Thanks for the offer of doing a special order, but I think I will continue to pester my FLGS and hope that they in turn get the distributors to re-stock the books. I had books shipped from the US to me in the past, the price for shipping can reach about 40 $, depending on weight (I think if it is over one pound of weight), so this would be a last resort for me.
Stefan
So, finally, after ordering several of the books I mentioned above at once a while back, my FLGS got them today. Seems that the distributor only ordered the books when he got orders for several of them, or something like that. But be that as it may, I immediately bought several books, and the store will keep the others in stock, unless somebody else buys them first. Everything is fine now 
(At least until the next book is published...)