In 1919 a returning World War I veteran named Harry Hahn and his French bride attempted to sell what they thought was a painting by Leonardo Da Vinci in New York. Renowned art dealer Sir Joseph Duveen declared the picture-La Belle Ferronnière-a fake without ever seeing the canvas. The Hahns sued Duveen for slander, setting off a legal battle that would last for decades. In The American Leonardo, John Brewer traces the twisting path of the Hahn La Belle-a painting of famously uncertain origin--as he illuminates the workings of the twentieth-century art market, exploring such larger questions about the art world such as how attributions are made, how they affect both the status and value of artworks, and how the entire system of art dealers, curators, and connoisseurs authenticates works of art. In the early twentieth century new methods of scientific analysis developed, which meant that for the first time, the critical eye of the connoisseur had to contend with an emerging array of scientific and forensic tests that (however crude at their inception) promised a degree of objectivity and reliability unattainable before. Brewer shows how the tension between the two methods of attribution lay at the heart of the Hahn La Belle dispute, which continues to this day. The painting currently languishes in an Omaha storage vault awaiting the resolution of the most recent lawsuit. For artists and art-lovers, collectors and curators--and for anyone who's ever stood in front of a painting and wondered about its story--The American Leonardo offers a discerning and entertaining view into the art world.