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 Colours, a grid of monochromatic squares 64 tall and 64 wide (for a total of 4096 squares) which was organized and designed according to a mathematical formula that systematically mixed red, yellow, blue and gray.

Photographs of the work are accompanied by three essays that integrate this important work into the context of Richter’s oeuvre and shed light on the principle of randomness on which it is based.