The most celebrated painting in the world and the center of endless speculation and investigation, Leonardo da Vinci's Mona Lisa retains much of her mystery. Who was she? What is the reason for her faint smile? When exactly was the work painted, and why are there no sketches or studies? This study combines close-ups, X-ray photos, painted copies, and similar works to examine the enigma. This is one of a series of compact monographs that present visual surveys of a specific cultural phenomenon or personality captured in photographs. Following a concise introductory essay, each presents dozens of large, uncaptioned color and black and white plates—some filling both pages, 12 x 8 1/2 inches—which are identified in a thumbnail index. Most titles in the series include a chronology or bibliography.