In 1845, a Reading bookseller named John Snare came across the dirt-blackened portrait of a prince at a country house auction. Suspecting that it might be a long-lost Velázquez, he bought the picture and set out to discover its strange history. When Laura Cumming stumbled on a startling trial involving John Snare, it sent her on a search of her own. At first she was pursuing the picture, and the life and work of the elusive painter, but then she found herself following the bookseller’s fortunes too – from London to Edinburgh to nineteenth-century New York, from fame to ruin and exile. An innovative fusion of detection and biography, this book shows how and why great works of art can affect us, even to the point of mania. And on the trail of John Snare, Cumming makes a surprising discovery of her own. But most movingly, The Vanishing Man is an eloquent and passionate homage to the Spanish master Velázquez, bringing us closer to the creation and appreciation of his works than ever before.