A marketing friend of mine once asked:
If you want to drill a hole in the wall, but you don't have a drill, what do you do?
Then I borrow one or buy one at the DIY store.
Yeah. But why do you buy a drill?
How for what? I need it to drill a hole in the wall.
Big mistake! You don't need a drill, you need a hole. The drill is just one tool to accomplish this.

If you need to

after a few hours of "studying" from a thick book, successfully pass the exam...
read a large amount of material in a short time...
reach a higher level of understanding...
your acquired knowledge should be more permanent...
learn languages ​​more easily...
easily recall what you read...

Then you need the drill!
I want to say... to Lightning Reading!