If you are interested in reading more about neurofeedback, here are a few recommended books. Some are a bit more basic (*), others a bit more academic (**) and some are quite technical, designed for advanced professionals (***).
Longo, R. A Consumer’s Guide to Understanding QEEG Brain Mapping and Neurofeedback Training. Foundations for Neurofeedback Neuromodulation Research.
Not a bad short intro. I - Jeff - disagree with some of the generalities Longo makes, and his intro does not cover the advanced nature of TNC’s neuroanalysis.
Van der Kolk, B., The body keeps the score: Brain, mind, and body in the healing of trauma.
Van der Kolk is one of the top researchers in PTSD and has come to the conclusion that NFB is by far the best and most promising treatment currently available.