Merging hard science and metaphysics, Cooper explains what light is, how we perceive it, and how to use it in the treatment of disease. She offers an excellent discussion of the pioneering work of Rudolf Steiner and Dr. Norman Rosenthal, who developed full-spectrum light treatment for Seasonal Affective Disorder, as well as the work of Barbara Brennan (Hands of Light) and Peter Mandel, who merged light therapy and acupuncture. Auras, the Seven Rays, Traditional Chinese Medicine and the chakras are also covered.