Almost everything in the sky is invisible to us, and that is the premise The Invisible Universe takes as its starting point. Visible light is a narrow slice of the spectrum, and astronomy spent most of its history looking through the only window it happened to have.
Matthew Bothwell writes on our science and engineering shelf and reads the recording personally. Popular astronomy carries a particular hazard, that of turning wonder into a slideshow of adjectives, and a writer narrating their own work tends to keep the explanation exactly where the argument put it.
That is what our record supports, and we leave the rest alone.