LIGHT is the overarching theme of the 9th Imagine Science Film Festival this month, but its significance extends far beyond any one festival or month of programming, since it lies at the heart of both film-making and scientific observation. But the meanings of light multiply far beyond even these. These films deal with visual reception by eyes and cameras, with the blinding flashes of nuclear tests and weapons, with the life-giving process of photosynthesis and the destructive effects of too much light in coral bleaching. It can equally serve as metaphor for religion or wisdom. And of course light suffuses the history of science, here informing both real and imagined breakthroughs. It is, of course, no coincidence that sudden understanding may be described as "illumination".