If by that you meant to suggest that for formal study, some kind of self-review process combined with cold written practice/rehearsal sustained under interleaved spacing, then that is likely the gold standard for comprehension and memorization. But most people don't even know that, either.
But the main premise is we should not assume all book reading is for rigorous self study. Margin notes can be useful for other purposes than direct understanding/retention (I admittedly don't know the psychology evidence for it but many academics routinely write margin notes here and there on (poorly written/edited) papers for purposes of idea generation, scientific criticism, etc. Presumably the Edison example mentioned above would have been more like that.).