Lloyd Currey is one of the great names in the field of science fiction collectibles. He stocks some of the finest and rarest books, and over the decades has seen almost everything the field has to offer. He’s not unique in this. Other dealers have catalogs as deep as Currey’s and their books can be just as rare and valuable and collectible. You can figure out who they are pretty quick by going to a meta-search site like Bookfinder.com and entering a Gnome title. When the results appear scroll down to the bottom of the page and look at the ones with the highest price tags. A few dealer names will pop up over and over. I’ve bought books from most of them, and they give equally good descriptions and equally good service.
Currey gets a special page because many years ago, when print references books still made sense, he compiled his collected wisdom about the works of the major authors in the field in Science Fiction and Fantasy Authors: A Bibliography of First Printings of Their Fiction, published by G. K. Hall & Co., Boston, 1979. (This is the edition I’ll be referring to when I write CURREY. A revised edition appeared in 2002 from rb publishing. The Gnome information is not much changed, although I’ll mention it if appropriate.) The almost 600 pages examine every known title from 200 of the most important authors in the f&sf genre up through 1979. For each he gives what is known (or at least thought) to be the earliest printing, along with any identifiers that help to distinguish variants – states – of that first edition.
Here’s an example:
Lyon Sprague de Camp
TALES OF CONAN. New York: Gnome Press, Inc., Publishers, 
Five bindings, earliest as listed, but sequence for remainder not established: (A) Red boards lettered in black; (B) Green (boards?) lettered in black (not seen); (C) Black boards lettered in red; (D) Gray boards lettered in red; (E) Gray cloth lettered in red. First edition so stated on copyright page. With ROBERT A. HOWARD.
If you do the search on Bookfinder, you’ll pull up a dozen or more copies of this title. If all you want is a copy of the book, then choose what condition you want and how much you’re willing to pay and put in an order. That’s all the information most of the listings give. However, you’ll also see references to “fourth state binding” and Currey binding “E”. That’s an important distinction if you’re trying to collect all five bindings.
The Currey state is a critical piece of information, therefore, and for the vast majority of Gnome titles, the only clue about variants most dealers will put into their listing. Almost no one ever mentions CHALKER in a listing, even if those few cases where he differs. For Tales of Conan, in fact, he puts the red boards as the first binding and the gray cloth as the second.
Finding a state Not In Currey is a rare and blissfully triumphant get for any collector. As far as I know, no one site offers information on states that Currey doesn’t mention, which is the major reason I’ve started this project. I’ve just stumbled over these variants over the years, not knowing they existed. There may be others out there. There may especially be others for books whose authors aren’t listed at all in CURREY. The overwhelming majority of dealers don’t bother listing the boards and lettering for titles not in CURREY. That might be a major omission, hiding a rarity. If you know of any, please think of this page and send in a comment. I’ve already found a few and are listing them under the heading Not in Chalker. Over time, together, we can tease out all of Gnome’s secrets.