The questions keep branching out. What is the drawing meant to show? Empty spaces on the shelves? So then the geezer is being sarcastic about “I wouldn’t have any of that stuff in my library”? Or they really are audiobooks, on physical CDs with shiny plastic cases? And then Zack is dumbfounded because he has never heard of audiobooks? Or instead, Zack is dumbfounded because he is quite familiar with audiobooks, but always in electronic or virtual form and never before this in a physical recording?
Comics I Don't Understand 
I think it’s about the audiobooks being in the cloud and not paper copies. To highlight the difference between listening to a book and actually reading the physical item. But in that spectrum, where does reading a Kindle edition fall?
The audiobooks that my kids (and my dad) have are on CDs, and usually reside in the car, not on a shelf in the house.
P.S. I don’t know about that “modern” piece, but “The Philosopher’s Song” is a classic.
The impression I got is that the audiobooks are invisible because sound waves aren’t visible. It’s not a physical medium, but the audiobooks are composed of sound that exists within those empty spaces on the shelves.
@Powers, some version of that idea is also the one I’m most attracted to, in general, but can’t quite really make work. The spaces in the drawing aren’t really like traces of sound waves, and only a little like spectrograms.
maybe a clue is in the earpiece.. Hearing aid (I think) for loss OR blue tooth or gain.
@Mitch4, I wouldn’t expect any sort of visual artifact for a purely invisible phenomenon.
Wait, maybe just cloth-covered speaker boxes?
“The Philosophy of Modern Song” is not itself a musical piece, but a recently-published book. And yes, it is available as an audiobook, even in the Audio CD physical format. I don’t think it has anything much to do with the cartoon.
Our library of audio books is on Audible, in the cloud. We download the one we want to hear and listen to it. No shelf space.
Just like moving over to streaming music frees up all that space once devoted to LPs or CDs.
Of course, with Kindle, much of my reading library is also in the cloud.
I’ve never had any interest in audio books. The only time they’d be at all useful to me is while driving, but I don’t go long distances by myself much at all these days. Mostly I listen to music.
Many’s the library that has been donated to start a college. Not so much nowadays. When I am stuck somewhere with only a small bed stand, I will have long since shed all my precious books – they wouldn’t allow them in the ‘home’. So I’ve been going with Kindle and Audible. Theoretically they will always be available to me. But, maybe only me. I suspect somewhere there is a README that I’ve signed saying I only have a license for these items. (Like the Windows on my computer.) I recall that Kindle has taken back books without our knowledge when copyright problems occurred. So, I interpret the cartoon to only need the caption “Someday this will all be yours.”
Agree with Powers, you can’t see sound.
Robert has been listening to many an online audio book since the pandemic started. He found out that he can download same and ebooks from the public system in our county – and later found out that they have an agreement with Brooklyn library so he can do same from them. Since his cataract surgery some years (decade or more) ago he has not been comfortable reading as he cannot really get used to his prescription reading eyeglasses (never wore them before, though he now needs glasses for driving also and has adjusted better to them). He can make the ebooks on the computer very large to be able see them without his glasses.
Though the library thinks I am the one borrowing and reading them as he could not find his card and I gave him mine. I finally found his card in my desk drawer with our business cards and some other cards I keep there – why it was there I have no idea.
He can make the ebooks on the computer very large to be able see them without his glasses.
That’s a big reason why I switched to pretty much all e-reading, although I use my iPad mini. Also because I can get books at any time.
Brian – I find it hard to read and follow what I am reading on a screen and if made larger it is even worse it is the moving up and down of the page. I have been known to print out pages of IRS forms instructions to be able to read them – when I needed a new monitor Robert bought me one which can be turned vertical in addition to the normal horizontal figuring that seeing the entire page might help me – not really.
When reading a book, that really isn’t a concern.