"As a nine-year old, Joan Di Stefano's experience of a light-filled church was a turning point. Her story inspired our theme and, when I began thinking about the action of light, I quickly realized it goes beyond what we can cover in this issue. Everywhere light is synonymous with the sacred, for instance. And I've read that our eyes are so sensitive to photons that just a few can trigger a perception. So our seeing of light extends to the level of elementary particles, a spectacular thing to ponder. There's inner light, too. James Turrell said, in issue #2, that his grandmother told him to go inside to greet the light. There are many ways to think about it. And each feature here resonates with our theme in its own way." Editor's Introduction