Andrew Ladis begins his book with Giorgio Vasari's famous story of Giotto's O, in which the artist drew a perfect circle freehand, baffled Pope Benedict XI's foolish messenger, and demonstrated his artistic brilliance to those qualified to understand. The fundamental premise of Ladis's work is that the Arena Chapel, like Giotto's mythical O (or tondo), must be understood as a complete, unified whole. He tells us, "the cycle of murals in the Arena...