I want to post the book The 1980's Countdown to Armageddon after I get a good laugh out of it (author's prophecy that the rapture would happen by 1988). The only problem with the book is that it was published before ISBNs were added and it has never had a reprint. Is it possible to add a book without an ISBN?
 

If you click on Post Books under My account, there will be a section in the lower right on that screen that talks about posting books without ISBNs and a link "click here" that takes you to the screen to enter the information to post it. PBS will assign a 6 digit number to your copy. 

Thanks.

The ISBN-10 numbering system was established in the late 1960's and came into common use approximately 1970. Even so, many books published after 1970 do not have ISBN's.

The ISBN-13 numbering system was adopted in 2007 but, again, not all publishers use the either of the ISBN numbering systems. It is not uncommon, for example, for book club editions and books from small presses to not have ISBNs, regardless of date.

ISBN-10 numbers and ISBN-13 numbers can be easily converted from one to the other using a mathematical formula.

Thanks for the history lesson, Chris.  That's interesting as we were members of several children's and adult book clubs between 1983-96 and all of them except a set of classics have ISBNs.

The ISBN system is varied.  First, in the US using ISBN's is voluntary by a publisher (they have to pay a fee for the issuance of ISBN blocks ISBN.org).

For this reason, many book clubs (but not all, it depends upon the book club, my uncle for example belongs to a book club whose primary purpose is to issue leatherbound first editions, I drool everytime I see his library, but you better believe they have ISBN's), do not pay for the issuance of these identifiers, especially if they are the listed publisher (their purpose is generally to save their members money after all).  Additionally locally published books (for example I am currently trying to collect all of the nature guides published by the Missouri state parks) will rarely have an ISBN.  There are also some publishers that don't use this (the only one that comes to mind currently is Reader's Digest, which is also sort of a book club).

Additionally there is the other problem that I encountered where a book's ISBN is not visible anywhere on the book (even though I am certain that it has one, given the publishing date, publisher and some research).  Amusingly enough I've found this to be most true with Hardbacks.

If you are really upset about this (I'm not, personally I would prefer that publishers be required to list the library of congress number in the book, not to mention the fact that as the internet continues to change our culture I see publishing taking further changes), I have seen a lobbyist organization that is currently trying to make legislation that will set aside free ISBN numbers for different things (I couldn't find the link, but I saw them a few years ago when I looked up ISBN's)