Books and lectures don’t work

All this suggests a peculiar conclusion: as a medium, books are surprisingly bad at conveying knowledge, and readers mostly don’t realize it. Books don’t work for the same reason that lectures don’t work: neither medium has any explicit theory of how people actually learn things, and as a result, both mediums accidentally (and mostly invisibly) evolved around a theory that’s plainly false. If pressed, many lecturers would offer a more plausible cognitive model: understanding actually comes after the lecture, when attendees solve problem sets, write essays, etc.

Source: andymatuschak.org