Read the article in the PhotoReading section, "Works on all Material," and activate until it gels.
There are times that nothing in the book seems familiar to me, until it gels. That's how I know it is time to quit activating. Because it gels. It comes together. I know the material.
Do I know or remember everything in the book? No, but I would do quite well on a comprehension test.
Actually, most books or the information they contain are not worth the time. It is folly to think you have to know everything. What's the value?
A few exceptions involve studying for school, but even professors will admit that much of the information in books have little value (unless the professor wrote the book, and believe me, I've heard from professors who say that every word in their book is vital. "I've labored over every sentence, every word. I don't want anyone going through this book unless they consider every detail the way I present it.")
Jiminy Crickets.