CN number

I'm not sure if this is the correct forum, so please re-direct me if it's not.
Several of my books do not have ISBN numbers even although they're relatively recent. However several of them have a CN number. I can't find any reference on the site. Could someone identify this code for me?
Thanks

What does this number look like?

Is it a Library of Congress Call Number?

If you provide an example or two - title and the CN number, someone may be able to identify it.

If they are all from the same publisher, maybe this is an internal catalog number?

LCCN is Library of Congress Catalog Number, but you'd have to give some examples to know if it's that. Usually the format in older books is 00-0000, where the first two numbers are the year and the rest is an accession number. I can't recall how many numbers came after the dash, but I'm sure the info can be found online somewhere.

A while ago I came across some books in my personal collection where in place of an ISBN they had a number which began CN - all of the books in question came from a mail order book company (the kind where each month you received a pamplet of books and you had to buy a minimum of x each month and if you didn't choose, they would send you one that they picked for you anyway). I was only in my teens at the time, so it was my parents who had the subscription. If I remember rightly I entered the books manually leaving the ISBN blank. As in my case most were classics (e.g. Jane Austen) I was able to add them to the available editions, but they are left needing a valid ISBN.

>6 Peace2: Your books do not HAVE a valid ISBN. An ISBN for a later edition would be wrong for your copy.

I assume you have paper books, right? An ebook sold by Amazon needn't an ISBN, since they use their ASIN code. (Note that ebooks in epub format do have a ISBN which is different from the one(s) for the paper edition(s). Every edition of a book has a different ISBN).
I agree with the former comments: some examples would help a lot in understanding what is happening.

Recently published books will have an ISBN for that edition if the publisher chose to pay for one. This became the standard during the 1970s.

Best practice is to have different ISBNs for different editions, and certainly never to use the ISBN of an out-of-print book for a new book. However some publishers don't worry much about good practice, never mind best. Self published books often don't bother with an ISBN.

> Anniemod
I'm going to have to go back through my books. But one is Words - An illustrated history of western languages, edited by Victor Stevenson. 1983 - Book Club Associates by arrangement with Macdonald & Co. I have other BCA books which have ISBNs but no CN no.

Sorry - CN 6378

> MarthaJeanne
The format is CN XXXX

>10 B.S.M.: The title of the book isn't really helpful without the number. If the CN is the LCCN, then it will probably be 83205642.

>10 B.S.M.:

Some Book Club editions didn't (and probably don't still) have ISBNs.

Words - An illustrated history of western languages

From the book details page on LT:
(But this might be a newer number)
LC Classification P541 .S67

>13 gilroy: Not the classification.

LCCN Library of Congress Control Number - see >5 tardis:

You can look books up by LCCN in both LoC and British Library. Probably some other libraries as well, but I've used these two.

>10 B.S.M.: These are BCA editions? BCA and other Book clubs publishers usually have their own catalog number for their books. They may have ISBN for some (but not all) but they will have a Catalog Number for all their book (although some may not be printed and that rule may have been different through the ages). That sounds like one of these catalog numbers of BCA...

I don't know what happens in the USA for Book clubs and similar, but I do know that in Italy kiosk editions usually don't have ISBN. They are equated to magazines, and therefore a single ISSN is used for all the books issued.

Many books don't have an ISBN. The system came into use around 1970 (so anything before that). It was intended for distribution, so exhibition catalogues that were only sold at the event itself rarely had one (I have lots of those). Now, with ebooks, we face things like ASIN. The list of reasons keeps growing.

ETA: And I can imagine book clubs not using them. After all,they have their own distribution system.

None of my Folio Society books have an ISBN

>18 B.S.M.:
Folio Society does not assign ISBNs to their books - so they will never have an ISBN