I have an old Silhouette romance that I was going to post.  When I put in the ISBN number that is on the copyright page of my book I came up with a whole other work.  I have Pride's folly by Tracy Sinclair but it lists as Maverick Moon by Jane Archer.  The ISBN number is 0671537083.  Weird.

Here's the story, William. When Harlequin bought Silhouette from Simon and Schuster in the late 80's, Silhouette started using Harlequin's ISBN prefix (0373) while Simon & Schuster, in their dubious wisdom, started reusing the ISBNs that had originally been assigned to Silhouette. Publishers have to pay R.R. Bowker (the exclusve agency responsible for maintaining the ISBN database and issuing numbers) for each ISBN, so they thought they'd save a little money. I see the 0671 series pop up most frequently attached to Star Wars serials that were published in the mid 90s.

I'd suggest using this link to list your copy: http://www.paperbackswap.com/book/details/248524-Prides+Folly

Colleen 

It's not uncommone for publisher's to reuse ISBN #'s. Usually  they  do it for a different bidning of the same book. But they  also use it for completely different books. you have to post it without an ISBN. 

Thats the one I used.  I came up with the problem again on a Harlequen Presents book.  I just gave up on that one.

You can always do the "post a book without an ISBN" thing. You really never know when someone is looking for one of those older books, and if they are determined they will look under author, title, and ISBN.