And that is no easy feat. The man was a genius and it's not always easy to understand. On the surface the concept is the idea of "Lydian as Tonic", meaning that the Lydian Scale becomes the one on which you base your modes and chords. It goes much deeper than that though. "Tonal Gravity" is another term used, the idea that the scale with a sharp forth/flatted fifth has a stronger pull for the ear than a regular major scale:
F G A B C D E F (F Lydian) as opposed to
F G A Bb C D E F (F Major)
The book is rather expensive; I paid $135 for mine but I think it is worth it to own a copy. I actually borrowed mine at first from a university music library, read it, then decided I needed to own it in order to read it again. I'll probably need to read it several times. And, to really get it, you ought to have a keyboard to go over the theory. You don't have to be able to play, you just need it to really understand the theory, to see how the chords work. They go beyond the scope of the guitar at points.
I always suggest people interested in LCCOTO watch this, from 1958:
You get to hear the maestro himself talk about it and you get to hear some compositions based on it. Mundell Lowe is on this video so you get to hear a great guitarist too.
Another great vid on George Russell:
It's would also be a good idea to listen to some of his records, which are out on CD and easy to get. My two favorites are "Ezz-thetics" and "Stratusphunk".
George Russell passed almost exactly a year ago; July 27, 2009. His contributions were legendary. You wouldn't have Miles or Trane without George Russell; so much of their ground breaking work was based on his concepts. He began as a drummer but when he heard Max Roach play he decided to become a composer.

He played the piano in his groups; not really on a virtuoso level but well enough. When he was asked if he considered himself a piano player he replied "I don't play the the piano, I play the Lydian Concept."
LCCOTO generates a lot of controversy on some boards I've visited people love it, hate it, argue about it, the usual stuff. The books you have are fine and for the most part were written to present it in an easier to understand manner I just think it's necessary to go to the source. Just remember that in the end it's about playing music and not concepts.
George Russell's Lydian Chromatic Concept of Tonal Organization
and
George Russell