Christopher Snow is the best-known resident of 12,000-strong Moonlight Bay, California. This is because 28-year-old Chris has xeroderma pigmentosum (XP)-a light-sensitivity so severe that he cannot leave his house in daylight, cannot enter a normally-lit room, cannot sit at a computer. Chris's natural element is the night, and his parents, both academics, chose to live in Moonlight Bay because in a small town Chris can make the nightscape his own-roaming freely through the town on his bike, surf