A few questions about ISBNs?

The ISBN is specific to published books. That the CD you were given has an ISBN leads me to believe that it is an oration of a published work. An article would not have an ISBN but the magazine the article is published in would. The ISBN is also very specific. A title published in hardback, paperback, as an audio CD, would have a different ISBN for each. Any addition or deletion from a published work, revisions that make a significant change, would also require a new ISBN. Diplomas, certificates and such would not have an ISBN. All ISBNs are issued by R.R. Bowker, and you can read more on them at the link below.