Agreed with Rhys, if i am reading fiction then i read it once and move quickly.

However there are books that are not meant to be read quickly . SOmeare meant to be read twice like 'How to win friends and influence people' or i read 'Getting to say yes' twice/

We need to grasp what it is talking about so that we grasp the intent.

I have started to read 'Biology of belief' and i need to read and re read sentences to understand what author is conveying.

I think the technique depends on the kind of books you are reading.