Get the book, they last longer and ride well on a shelf. Take notes as you read it. Reread the notes before you hit the trail and/or at regular intervals. Thumb through the book every year or two and check against your notes. Often the bits I thought were the most important a few years ago are different from what I consider the most important points now.

A working and conceptual understanding of the information is more important than memorizing the text. Don't worry so much about what it says. Focus on as what it means and how the details fit into the larger context.

You could slip an outline copy of the notes into your kit, they can be a useful refresher, but when an emergency rolls around you will be operating entirely off memory.

If you have time to read you're not in an emergency. If you are in an emergency you won't have time to be reading anything. Learn it. Study it. Put a copy on the mirror in the bathroom and another copy on the refrigerator. Make it a rule that you can't use the sink or refrigerator until you read or recite the outline notes. Do what you need to do to get it into your head where it will do you some good. In the end you have to be willing to do the work.