I am new to the site but have spent quite a bit of time trying to figure it all out.  Here is something I cannot figure out: I looked at the wish list items and typed in a book I had on my shelf.  I saw that two people wanted this book but when I clicked to post the book the ISBN numbers didn't match, so I didn't post it.  It's the same book so what is the deal here? 

Hi Rachel, and welcome to PBS!

The deal is that it's the ISBN that defines the book - so two books that have the same title and author but different ISBN's are actually different books. They may tell the same story, but they are treated differently. One might be a paperback, the other a hardcover or large print. Different editions will have different ISBNs; one may have a different introduction or some other difference. Some may be almost exactly the same, too - but it's the only way to differentiate. So it's not really safe to assume it actually IS the same book, even though it may seem like it.

The good news is that most people know that a book may have multiple editions and if they really want it, they'll have taken that into account.

The most important thing is to be extremely careful to post a book properly - the ISBN, the title, the author, AND the binding type must all match what's in the database. What happens if that is not the case? (when this happens, it's usually the fault of the publisher) You can still post, but you must post it using the "No ISBN" option.

Just read and follow the instructions  that come up during the posting process and you'll be fine. Another thing you can do is to put a "tag" (a user-defined annotation) on the Wishlisted book that is similar to your own, indicating that there is a similar edition available from you. That way interested parties can visit your bookshelf without a book being misposted.

Again, welcome and I hope you like it here! (and that this helps)

There are a lot of different versions of the same book.   There are hardbacks, mass market paperbacks, trade size paperbacks and book club versions, and reprints to just to name a few.  Some people want one book over another for different reasons.   Post your book by the ISBN number - you can also look the book up by that number to see if that particular book is wishlisted.

Hope this helps.

Ok, thanks so much for the help.  I didn't know about the tag option also, so thanks again. 

Publishers change over time as well. 

Some people also collect hardbacks or specific cover series and many people need large print.