A Symphony in the Brain: The Evolution of the New Brain Wave Biofeedback," by Jim Robbins, Atlantic Monthly Press, $24.

When the author of this book first heard of a technique known variously as brain-wave biofeedback, neurofeedback and neuro therapy, he was battling chronic fatigue syndrome and had exhausted traditional therapies.

Though it "had a New Age whiff about it," he nonetheless traveled to a weekend symposium, got his scalp hooked up to a computer display via electroencephalogram sensors and began a session of brain-training.

"After a half hour," he recalls, "my mind was tired, my thoughts muddled. But an hour or so after I finished, I experienced what is known as the clean windshield effect. The world looked sharp and crystalline, and I had a quiet, energetic feeling that lasted a couple of hours. It was the first time I had felt that way in years."

Biofeedback, which has been around for some 30 years, harnesses the body's natural rhythms — brain waves and autonomic functions — to monitors that allow one to see, for example, amplified electrical frequencies of the brain or usually unconscious occurrences like blood pressure and heart and lung action.

By watching these events on a computer screen, participants are able to influence their physical and mental well-being. In neurofeedback, patients can be trained to operate in brain frequencies they do not generally use, an exercise designed to enable one to strengthen the brain.

He argues that though the medical profession is generally dismissive of the therapy, the effects of neurofeedback are "not subtle but extremely robust."

It may not be either miracle or panacea, he writes, but it is science, albeit science that is still young and relatively unknown. The big question about neurofeedback, he concludes, is not whether it works, but "why it is as effective as it is, for whom, precisely, and how it can be made more powerful."