In 1992, when Henry Grunwald missed a glass into which he was pouring water, he assumed that he needed new eyeglasses, not that the incident was a harbinger of darker times. But in fact Grunwald was entering the early stages of macular degeneration -- a gradual loss of sight that affects almost 15 million Americans yet remains poorly understood and is, so far, incurable. Now, in Twilight, Grunwald chronicles his experience of disability: the clouding of his sight, and the daily struggle to overcome its physical and psychological implications; the discovery of what medicine can and cannot do to restore sight; his compulsion to understand how the eye works, its evolution, and its symbolic meaning in culture and art. Grunwald gives us an autobiography of the eye -- his visual awakening as a child and young man, and again as an older man who, facing the loss of sight, feels a growing wonder at the most ordinary acts of seeing. This is a story not merely about seeing but about living; not merely about losing sight but about gaining insight. It is a remarkable meditation.