My son had to read classics for English this year at school and now that he is done with them and we are getting ready to move we were looking to post them, but most were written before ISBN numbers were put on books so my question is do more people read posts in bazaar of books without isbn number or should I take the time to measure and list without isbn.  Trying to figure out the best way that more people would see them so that I can get them out.

ISBN were started in the 1970s.  Older books may have the 10 digit on on the spine or copyright page. 

I would suggest listing the titles and offering a deal  (3 for 2, or whatever) in the Book Bazaar and/or the Classics forum.

SBN's began around 1965 and  were 9 digits. This soon expanded to 10-digit ISBNs in the late 60s and came into common use by the early 70s. The system was expanded to ISBN-13 around 2005 and standardized in 2007. Not all books published since the ISBN system came into being have numbers assigned to them, so lack of a number does not necessarily indicate that a book predates the numbering system.

Many books are posted and traded on PBS without ISBN numbers, and I don't think that posting without an ISBN is much of a deterring factor. But as with all listings on the site, with or without ISBNs, the more important factors are whether the listing has a cover image and description. Additional information such as publisher, publication date, number of pages, etc. are also helpful for trading. Books that are not well-known and that do not have cover images and descriptions are more difficult to trade.
 

Chris,

That was really helpful, thanks for posting it! I didn't know when ISBN's began but I have a book without one. I'm happy to know that I can post it ok if I decide to (it meets conditions but it doesn't have an ISBN). Good info :-)

Please be very careful entering the author's name if you are posting a book without an ISBN.  The exact spelling of the author is how our data base links versions of the books.  Skipping or adding a middle initial can make the book appear or not in the links.  (The links also trigger the another version of the book email.)