As a dinner-table antidote to persistent American nonsense and in preparation for next year's Europe-wide exhibition of Leonardo, Charles Nicholl, in appealing measure biographer, historian and travel writer, offers everything there is to know about the great master and much else besides. It is a hefty 622 pages, well illustrated, thoroughly indexed for browsing and footnoted for further study; which is not to say this is a daunting book. Nicholl's well-honed skills - he travelled the Orinoco tracing the journey of Sir Walter Raleigh, and explored Africa on the trail of erstwhile poet Arthur Rimbaud - and lightness of touch make this at once readable and definitive as he recreates the sometimes lurid and often heretical life Leonardo lived and how it inspired and inspires. The homoeroticism of his angels, including an erect full-frontal Angelo Incarnato, is only part of the story, as is the fact that Mona Lisa is a 19th-century name for a 15th-century painting of a woman and lacking any significance except that it is exceptional, like the man who painted it.