ON THE COVER: Glowing from its recent cleaning, this Sistine Chapel fresco by Michelangelo depicts the family of ancestors of Christ. The “un-Michelangelesque” pastel hues emerging on the Sistine ceiling have stirred the art world to ask, “To Clean or Not to Clean?”, a controversy laid out and laid to rest in the article in this issue. To learn more about this picture and to compare it to its “before” appearance, see the detail of the Ancestors of Christ lunette.