How can I find out what a book is worth without a ISBN number?

I have mulitple books with no ISBN number and would like to know how much they are worth.|||A number of factors go into deciding the worth of a book. First, consider the author. How well known is the author? What is the demand for the writing of that author? Next, consider the content of the book, the subject matter and society's demand for the subject. After that, what is the page length, the word content of the book? Are there pictures, indexes, etc? Is there more than the actual written content matter? And finally, what is the cover like, paperback or hardback, and what are the pages like in paper type? All these factors go into deciding the cost worthiness of a book.|||As most books that are worth something don't have ISBN numbers then you are in luck,


Are theses text books, if so you are out of luck as only current editions are worth something.


Are they older books? It so, try looking on eBay for what people are asking for there.


And brace yourself.


The old book market is not what it use to be.|||Hi that would depend on the subject matter as isbn is now a standard which seems to be used only in the last 20 years.|||go to a local community college campus and ask, or call them.