You need the book.
Learning happens better when you are exposed to material in at least 3 ways: visual, auditory and kinesthetic. You can read the actual book, watch youtube videos at khanacedemy.com for material you don't get and make your own flash cards.
All of these combined is just an example of scientifically proven ways to learn.
Some people who have A's in all their prereqs and say that they naturally never have to work that hard to 'get' things are just popping up smoke. It takes practice, study and good old fashioned elbow grease with hard work and 'hitting the books' to get there.
Just like people who want to lose weight looking for a mysterious new 'secret' to lose weight when they know that diet and exercise are the fundamental ways to get there but they just want a shortcut.