The demo catalog is almost always up-to-date, generated with the bleeding edge code :
Sorry, but the Demo Catalog is not currently available. DropBox recieved DCMA takedown notices indicating that the contents were infringing copyright and so they disabled the DropBox account being used to host the catalog! That was a bit strange as we only provided download links for books that were in the Public Domain
We will try to find another location to host the catalog, and make sure that only public domain books have download links available so hopefully this time. This time a large disclaimer will be aded to the front page to try and make it clearer that copyright has not been infringed by the demo catalog.