The monumental Mole Vanvitelliana in the harbor of the Adriatic City of Ancona is the spectacular setting for a most original Leonardo exhibition. For the first time Leonardo's presence at Urbino and Pesaro as an architect and general engineer in the service of Cesare Borgia in 1502 is presented in a historical and cultural context that includes every aspect of Leonardos art, science and technology, and also his philosophical outlook. The rarely seen...

Bill Gates bought the Codex Leicester--a notebook of Leonardo da Vinci's scientific observations and theories--in 1994 from the estate of Armand Hammer for $30.8 million. Last year Gates loaned the work to Australia's Powerhouse Museum, which prepared this companion to its exhibition. No longer in codex form (the pages were bound in the 1600s, but Gates had the binding dismantled for digital reproduction), the manuscript ranges over topics from fossils...