What must a 'book' contain?

[Craig Morehouse <craigm@gdi.net>]

I hope this isn't too simple a question, but what are the _minimum_
elements that a printed work must contain in order to be classified a
"Book" that a Library could order?

Is an ISBN required?
Is a Library of Congress number required?

If neither of those, what kind of barcode or indexing would be desired?

If there is good reference of FAQ for these concerns, please point me to
it. I am going to be publishing works under Free Documentation License,
Open Publication License, and pure Public Domain.

I am trying to ascertain what a Library must have in order to order or
stock the book on their shelves. 

Thanks very much,
Craig Morehouse

-- 
"Person who says it cannot be done
should not interrupt the person doing it"
                     -Chinese Proverb