Neurofeedback as a clinical approach to the resolution of psychologi-cal and behavioral problems has its origins in the study of the brain’s electrical activity and behavioral psychology. The development of the human electroencephalogram (EEG) combined with the application of principles of learning, knowledge of the brain’s neuroplasticity, and principles of biofeedback and self-regulation have made it possible to detect, monitor, and change the brain’s electrical activity related to many emotional and physiological disorders. More recent advances in computer and electronic technology have allowed these research discoveries to be readily applied to the clinical setting. This chapter will present several of the basic concepts and principles that underlie the current practice of neurofeedback. Included will be a discussion of the importance of the electroencephalogram as a method to reliably assess and monitor the brain’s electrical activity. It will also review the principles of operant and classical conditioning as well as the contributions of biofeedback and self-regulation, as these provide the means and methods to change neurological functioning. In addition, this chapter will discuss the role of electronics and computer technology and software in creating a clinical platform from which to observe and direct neurofeedback intervention.