I have also found that I often forget entire books, and that quality of reading beats quantity. I use kindle and take a lot of notes. Then whenever I am in a s

I have also found that I often forget entire books, and that quality of reading beats quantity. I use kindle and take a lot of notes. Then whenever I am in a situation where I don't have a kindle and not much to do, such in public transport, instead of going on social media I use kindle app on my phone a flick though the notes, or turn them into flashcards and basically go over all the main points. Because you're taking notes throughout the book, you've created a kind of a map so it's very easy to refresh what you've read. I also like the idea of re-reading the best books again and again. I've got this from Naval's podcast. Some books are the condensed life knowledge, to read it once you won't get all the points. With great books, every re-reading you learn something new. It's better to acquire somebody's "life knowledge" in full depth and completely than accumulate a high number of shallowly read books.