Anything that maximizes the speed of information extraction from the book is obviously a win - whether learning to speed-read / skim or finding summaries[2] or "Cliffs Notes" or Anki cards.

Note that Anki is useful even if you don't have pre-made cards. Probably even more so. I've been working my way through CLRS lately, and I notice that I'm able that extracting all of the important content in a chapter and transforming it into cards takes maybe about 30-60 minutes. Previously I would spend much longer on the same material, and comprehend it much worse.

Admittedly this is my second read through the same material, after my first attempt to pass this course failed. So part of the speed advantage is probably in that I've had exposure to the same content before. But I also worked through a statistics course not too far ago, and even though I wasn't that fast there, I was still definitely quicker than if I'd have tried to read it the old-fashioned way.