--- ## Highlights books are surprisingly bad at conveying knowledge, and readers mostly don’t realize it. Millions of people have read each of these books, so that’s tens of millions of hours spent. In exchange for all that time, how much knowledge was absorbed? Like lectures, books have no carefully-considered cognitive model at their foundation, but the medium does have an implicit model. And like lectures, that model is transmissionism. Readers can’t just read the words. They have to really think about them. Maybe take some notes. Discuss with others. Write an essay in response. Like a lecture, a book is a warmup for the thinking that happens later. Great: that’s a better model! Let’s look at how it plays out. When books do work, it’s generally for readers who deploy skillful metacognition to engage effectively with the book’s ideas.