The term is used exclusively for recorded music.
I found this information on Liner Notes:
Liner notes (also sleeve notes or album notes) are the writings found in booklets which come inserted into the compact disc jewel case or the equivalent packaging for vinyl records and cassettes.
They are descended from the notes of text that were printed on the rear side of the cardboard record jacket used to protect a traditional 12-inch vinyl record, i.e., long playing or gramophone record album.
The term descends from the name "record liner" or "album liner".
On vinyl recordings, the most common placement of these notes would be the paper sleeve inside of an album jacket that served to protect the record from dust (dust sleeve or dust liner, etc.).
As the rear covering of an album jacket was applied in early days in a fashion that resembled the tailored lining of garments (overlapping and protecting the edges of the front cover), it's also likely that "liner" could have been a printer's terminology for this back cover area as well.
http://en.wikipedia.org/wiki/Liner_notes
Such notes often contained a mix of factual and anecdotal material, and occasionally a discography for the artist or the issuing record label.
They were also an occasion for thoughtful signed essays on the artist by another party, often a sympathetic music journalist, a custom that has largely died out.
However, the liner note essay has survived in retrospective compilations, particularly in box sets.
It is also a tradition in Japan especially for foreign artist releases in Japan.
A little more to read here:
http://en.wikipedia.org/wiki/Liner_notes
The Dust Jackets on a book are just that.
They are detachable and can provide biographical information about the author and a summary of the book from the publisher (known as a blurb), and puffs of critical praise from celebrities or authorities in the book's subject area.