In late 2010, art collector Peter Silverman revealed that a ""German, early 19th century"" portrait he had bought for $19,000 was, in fact, a previously unknown drawing by Leonardo da Vinci--an exquisite depiction of Bianca Sforza, rendered 500 years ago. In Leonardo's Lost Princess, Silverman gives a riveting first-person account of how his initial suspicions of the portrait's provenance were confirmed repeatedly by scientists and art experts. He...