Memory is built on 3 components:
A single one of these components can be enough to memorize anything. However, weaving the 3 components together is the most secure way to remember anything - once and for all.
Let me illustrate each component:
Impression: When you are very impressed by something (an idea, a picture, a sound, a face, a text, a situation...), the probability that you will remember it is much higher. For example, if as a child you were left alone lost in a mall for a while, you might remember the whole situation very accurately. Same with your book: if you are very impressed by something Thomas Jefferson did in his life, the chance to remember this part becomes higher. Now the good thing is that you can increase the strength of this impression yourself while reading. For example, you can stop reading one second and picture the situation in your mind, exagerating some features of the situation in order to enhance the impression of your mental image, by adding violence or greatness or anything to shock yourself. You can even add yourself in your mental picture, imagining Thomas Jefferson thanking you for your help or kicking your butt or anything like this. This will make the impression stronger.
Also, you may enhance the impression of a text by reading it out loud, even very loud if your neighbors are OK with it; some people are more sensitive to impressions coming from sounds (voice) than from the view (written text).
Association: If you can link something you read to anything you already know, the probability of remembering it becomes even stronger, sometimes incredibly strong. For example, if Thomas Jefferson was born on the same day as you, you would find it very easy to remember this, because you linked the data you read to something you already know for sure and will not forget. It is like tying something new (the data you read: Jefferson's birthday) to a tree (a piece of data you know: your own birthday) with a rope (the same date). That is why the more you know about a topic, the easier it is to learn more and more.
If you are very knowledgeable on a topic (like Christopher Hitchens and Sam Harris on literature), it becomes very easy to make strong links -- you have many ropes and many trees... So learn more about the basics and about the context of a book and you will remember more.
Repetition: If you read a book 10 times you will remember more. Same for anything, a recipe, a route between 2 locations, the lyrics of a song, phone numbers... The more you repeat, the more you remember. When reading a book, if you do not want to read it several times, you can highlight a few parts that you want to remember, and re-read only those parts several times. These parts you will remember much better. And you will see that actually they will also help you remember the rest of the book.
In summary: Impress yourself with powerful mental images, make associations with what you already know (and make sure you learn the basics before you learn more), and repeat this exercise several times. Work to become better at remembering and you will become better at remembering everything you want.