Brilliant study of the relationship between two fields usually kept miles apart: the physics of light and the metaphysics of the mind. Zajonc (Physics/Amherst College) begins with the curious problem of why blind people usually see only a blur when they first recover their sight. The solution is that ``without an inner light, without a formative visual imagination, we are blind.'' Seeing requires light and understanding. This axiom has revolutionary consequences, for it suggests that our very perception of the world is malleable: If we could see with greater consciousness, we would see--and thus inhabit--a richer cosmos. Zajonc traces this concept as it appears in mythology, science, literature, painting, and the history of ideas from Plato to Einstein. The ancient Greeks, he argues convincingly, did not perceive colors as we do; green was seen as ``moist freshness'' (e.g., blood was ``green''), while blue was seen as ``darkness.'' Why? Because the ``antique imagination'' differed from ours; perception has evolved through history--and so, too, has our comprehension of light. Euclid saw light geometrically; Robert Grosseteste imagined all matter as condensed light; Newton established optics as a mechanical science; in Planck's quantum mechanics, light maintains its mystery as ``a single thing with the universe inside.'' Zajonc seems equally at ease discoursing on atoms or angels, Zoroaster or relativity. He does so without fudging the science or fuzzing the spirituality, by seeing religion and science as essentially one enterprise, that of ``seeing the invisible in the visible.'' His two masters seem to be Goethe and Rudolf Steiner, both of whom held that, as Zajonc puts it, ``it is ourself whom we study in studying light.'' As our consciousness evolves, new perceptions beckon; in time, we may see that ``the natural world around us grows out of the moral world within us.'' A beautifully composed meditation that sheds new light on the nature of nature itself.