On the subject of books, there's an advisory email Carmack wrote to a kid years ago, telling him that his methods may be outdated compared to the modern advances in learning, but when he studied books he would read multiple resources describing the same thing because sometimes one resource may not transmitting information in a way that clicks to him.

I remember how insane it sounded to me that someone as talented as Carmack would look up for a second or a third resource describing a concept just because he couldn't clearly understand it on first try because, contrast to how we react when a student fails to grasp pointers. Our kneejerk reaction to someone not understanding a concept on first try would be "You want to re-read that again? Guess you're not talented. And you keep making mistakes after an hour? Sigh you're a lost case".

And here you have literally Carmack himself not caring how many books he has to reference, because all that it matters is that it will eventually click, he will own it, he will make progress and that's all that matters.