I don't mean that in a disparaging way. It's cute. It's endearing. It makes the book feel like a blog post or a zine, rather than a work of nonfiction to come out of a major publishing house, and that's part of the charm.
Yes, McLuhan did write a book called "The Medium is the Massage"
He *also* wrote a book called "The Medium is the Message"
and saying "McLuhan's famous book is actually called The Medium is the Massage" is ... not untrue, exactly? But it implies that you've only read one and not the other.
And the other is worth reading!
And even as I write that, I realize that I'm also wrong.
The Medium is the Message is the first chapter in Understanding Media.
The Medium is the Massage is the followup.
Regardless, The Medium is the Massage is the pop-art version of Understanding Media, and one without the other is still silly.