Ross King's "Leonardo and "The Last Supper" " Santa Maria della Grazie, Milan, Italy/The Bridgeman Art Library "The Last Supper," Leonardo's wall painting in Santa Maria delle Grazie in Milan. It has undergone deterioration and restoration since it was almost new. By the age of 42 (in an era in which life expectancy was 40), Leonardo da Vinci had yet to create anything commensurate with his lofty ambitions. At that point, Ross King writes in his new book, "Leonardo and "The Last Supper," " he "had produced only a few scattered paintings, a bizarre-looking music instrument, some ephemeral decorations for masques and festivals and many hundreds of pages of notes and drawings for studies he had not yet published, or for inventions he had not yet built." Too many of his projects - like creating a gigantic bronze horse on commission for Lodovico Sforza, the ruler of Milan - had gone unfinished; other projects having to do with architecture, military engineering and urban planning had not found patrons. Sometime around 1492, Lodovico began planning a family mausoleum at the church of Santa Maria delle Grazie in Milan. As the project expanded, he asked Leonardo to begin work on a painting of the Last Supper for the wall of the church's refectory, where the Dominican friars took their meals. "Leonardo may have dreamed of constructing tanks and guns, of placing a dome on Milan's half-built cathedral, or of completing the world's largest bronze statue," Mr. King writes. But he was going to do none of these things. Instead, he was going to paint a wall. The 450 square feet of paint and plaster known as "The Last Supper" would become one of the most famous paintings in the world - a painting, in the words of the art historian Kenneth Clark, that is "commonly held to be the climax of Leonardo's career as a painter" and that some scholars regard as a portal into a new era in art. In this volume Mr. King - the author of earlier books like "Machiavelli: Philosopher of Power" and "Michelangelo and the Pope's Ceiling" - gives us a gripping account of how that painting was created and how it represents, in his view, one of the few times in Leonardo's life that he managed to "harness and concentrate his relentless energies and restless obsessions." Mr. King deftly situates the painting in a historical context - against political events in Italy at the time, religious attitudes of the day and contemporaneous developments in art - and also places it in the context of Leonardo's career, deconstructing the ways the painter broke with tradition and stamped a familiar and much depicted subject with his distinctive vision. There isn't much that's substantially new in the book - Mr. King appears to draw heavily on the work of Mr. Clark and other Leonardo experts, like Martin Kemp, as well as on Leonardo's writings - but he does a fluent and insightful job of weaving together all his research. On several much-debated issues, Mr. King does not hesitate to serve up his opinions. He asserts that the girlish-looking figure sitting on Jesus" right is John - not Mary Magdalene, as a character in Dan Brown's best seller "The Da Vinci Code" famously argued. John, Mr. King contends, was traditionally portrayed as "a youthful and slightly feminine figure among his mostly bewhiskered and older companions." He says that one of Leonardo's sketches played with "the idea of placing John asleep on Christ's breast" - the way he was often traditionally depicted at the Last Supper - but that Leonardo ended up having John lean toward Peter instead in order to isolate Jesus spatially in the composition. As for the age-old question of whether "The Last Supper" depicted the moment when Jesus instituted the Eucharist or the moment when he announced that one of his disciples would betray him, Mr. King quotes a Leonardo expert who wrote in 1983 that most authorities had by then agreed that the painting represented "an amalgam" of both. What distinguishes Leonardo's "Last Supper" from the many versions done by previous artists? As Mr. King observes, the Bible's accounts were extraordinarily dramatic: a charismatic religious leader and his band of disciples gather for dinner "in the middle of an occupied city whose authorities are plotting against them, waiting for their moment to strike. And in their midst, breaking bread with them, sits a traitor.