When I want to understand something I don't read a book, I read multiple books about a topic. I did this and got quite informed about many useless topics (energy industry, austrian economics, history of science). Instead if I jump topics from one book to the next, I lose basically everything.
Also if you re-read books after some time, you get new insights.
As for programming (probably for anything you treat as a profession), I've noticed that you cannot beat practice, but if the topic is new to you, it's better to read the whole book first. It's much faster because you see what to expect and don't waste time when you practice on stuff that is easy and not as powerful as something else. Also you don't waste comfiguring tools only to discover that the tech doesn't really interest you anyway.
As for programming (probably for anything you treat as a profession), I've noticed that you cannot beat practice, but if the topic is new to you, it's better to read the whole book first. It's much faster because you see what to expect and don't waste time when you practice on stuff that is easy and not as powerful as something else. Also you don't waste comfiguring tools only to discover that the tech doesn't really interest you anyway.