I got my Nox for my birthday in April and still consider myself a beginner. I really liked The Equinox Series Handbook by Andy Sabisch. His "walk before you run" information and strategies are very useful for me.
But Clive's "From Beginner to Advanced" book brought the whole thing home for me. I'm a slow reader and have to re-read most things to get full comprehension, but for some reason the concepts just clicked for me. Clive's explanations of the way the Nox processes signal information and the related TIDs and his graphic representations of the different sounds made it much easier for me to understand. I've read that book 3 times now and think I grasp the principles involved. In fact, my detecting skills at local parks and my trip to beach have improved to the point that I'm fairly confident that I know what's in the ground before I dig it. Of course I still dig them all just to verify, but I'm probably 70-80% accurate.
I'm about half way into "Skill Building..." and understand it better now that I got the basics down. I haven"t started "An Advanced Guide..." yet because I'm not advanced yet.
Sorry for running on but I finally felt like I had something to contribute. 😉