The Mona Lisa Vanishes: A Legendary Painter, a Shocking Heist, and the Birth of a Global Celebrity

A conspiracy theory differs from a conspiracy in two ways. First, a conspiracy theory is when one attributes an event to a conspiracy by powerful groups with ominous intentions, especially when a simpler explanation is evident. Second, a conspiracy theory often exists in opposition to mainstream or expert views. Conspiracy theories tend to be associated with emotional and prejudicial beliefs, with believers imagining the reality they fear.

Cubism was an avant-garde artistic movement pioneered by Spanish painter Pablo Picasso, among others, beginning in 1907. As in the Renaissance, cubism was concerned with perspective, analyzing objects and people but for a radically different end. Rather than represent what things looked like in nature, cubism sought to represent the nature of reality by drawing attention to the artifice of a painted work. As Day suggests in the book, cubism was a response to the rapidly- changing modern world of multiple perspectives and cultures.

Alfred Dreyfus was a French army captain of Jewish descent who was falsely accused of giving military secrets to the Germans and subsequently convicted of treason. His case, which began in 1894, exposed antisemitism in France and divided French society. He was not exonerated and reinstated until 1906. The case has two purposes in The Mona Lisa Vanishes. First, it is an example of how assumptions create a false reality, as part of the French public was ready to believe the worst about Dreyfus because he was Jewish. Second, the case also featured Bertillon, whom Day mentions testified as a so-called expert that an incriminating letter was written in Dreyfus’s handwriting. However, Bertillon was not a handwriting expert.

Forensic science is the application of scientific methods—meaning methods for objective analysis—for matters of law, including solving crimes and disputes and protecting public health. Day introduces two of the early pioneers of these methods: the criminal-turned-detective Eugène François Vidocq and Edmond Locard. Considered the father of forensic science, Locard operated on a principle that if two things come together, they must leave traces, and the forensic scientist seeks to observe and record these traces. Day points out that forensic science can devolve into pseudoscience when methods are not objective and assumption-free, as occurred when Bertillon testified against Dreyfus.

The term “Renaissance Man” derives from Renaissance Italy, specifically from the Humanist idea that man is the center of all things and should be able to do all things. Day suggests in The Mona Lisa Vanishes that a Renaissance man is someone who is good at many things that have nothing to do with each other, which is how this term is understood today. This differs from how people of the Renaissance would have thought. For them, all forms of knowledge were fundamentally connected through their divine creator, and striving to know all things was a way to develop themselves to their fullest potential.

In Italian, the literal meaning of sfumato is to dissipate like smoke; it can also mean nuanced. As Day notes, it is an art term that refers to the technique of blurring the edges of images, allowing them to transition almost unnoticeably. It is closely associated with the work of Leonardo da Vinci, who developed the technique in part through his study of how humans perceive the world.

The Gilded Age refers to the period in the United States between the Civil War and the turn of the 20th century. It is named for a satirical novel by Mark Twain, The Gilded Age: A Tale of Today. The phrase had a pejorative intent to draw attention to the corruption that lay beneath the shiny, golden surface. During this period, the United States experienced tremendous industrial and technological growth, but only a small number of industrialists and bankers benefited from the ensuing prosperity. As Day explores, they sought to legitimize their new money by acquiring old culture, specifically art.