He mentions the book "How to Read a Book". I've read Mortimer Adler's version several times. It really changed how I read and learn from books. It's well worth the investment. I haven't read the Mortimer & Van Doren version.
I've found that doing the inspectional reading really helps. I've described it to friends as "giving me something to hang my hat on" while reading. Having the high level overview acts as a conceptual glue while reading a book through for the first time.
I think it was Naval Ravikant on an episode of Tim Ferriss' podcast that described reading as the "meta skill". If you can read you can learn just about anything.
Back to "How to Read a Book": Adler makes a distinction between able to read, e.g., "See Jack run", and learning from reading. I believe he describes 4 levels. The first, the ability to read, leading to the last, reading from multiple sources to learn. It's unfortunate that our ( U.S. ) educational system doesn't emphasize this much, or at all.