This volume documents Gerhard Richter's 65-foot-tall, abstract, stained-glass window for Germany's historic Cologne Cathedral, the original of which was destroyed by bombs in World War II, and thereafter replaced with clear glass. Composed of more than 11,000 four-inch squares, or "pixels," in 72 colors, the window is based on Richter's 1974 painting, "4096 Colors," a grid of monochromatic squares 64 tall and 64 wide (for a total of 4096 squares)...