When Gilded Age millionaires wanted to buy Italian Renaissance paintings, the expert whose opinion they sought was Bernard Berenson, with his vast erudition, incredible eye, and uncanny skill at attributing paintings. They visited Berenson at his beautiful Villa I Tatti, in the hills outside Florence, and walked with him through the immense private library--which he would eventually bequeath to Harvard--without ever suspecting that he had grown up in a poor Lithuanian Jewish immigrant family that had struggled to survive in Boston on the wages of the father's work as a tin peddler. Berenson's extraordinary self-transformation, financed by the explosion of the Gilded Age art market and his secret partnership with the great art dealer Joseph Duveen, came with painful costs: he hid his origins and felt that he had betrayed his gifts as an interpreter of paintings. Nevertheless his way of seeing, presented in his books, codified in his attributions, and institutionalized in the many important American collections he helped to build, goes on shaping the American understanding of art today. This finely drawn portrait of Berenson, the first biography devoted to him in a quarter century, draws on new archival materials that bring out the significance of his secret business dealings and the way his family and companions--including his patron Isabella Stewart Gardner, his lover Belle da Costa Greene, and his dear friend Edith Wharton--helped to form his ideas and his legacy. Rachel Cohen explores Berenson's inner world and exceptional visual capacity while also illuminating the historical forces--new capital, the developing art market, persistent anti-Semitism, and the two world wars--that profoundly affected his life.