I had a non-management colleague who did some management courses, and he commented that the course textbook had been incredibly valuable for his career.
Me: “Is it that useful a book for you?”
Him: “The book isn’t useful, on its own. What’s useful is the knowledge that all the managers in this place have the same book. So when a half-baked idea is announced that I know damn well they’re going to leave unfinished before they muddle off to their next half-baked idea, I can pull down the book, open the table of contents, look where they’ve read up to, and predict their next half-baked idea by checking what the next chapter is.”