'Unveiled: early copy that reveals Mona Lisa as her creator intended' by Charlotte Higgins, The Guardian, 23 September 2006.

"None of Leonardo's inventions ever took off, but an exhibition of his scientific drawings reveals how his extraordinary mind worked"
'New light on a high-flying genius' by Richard Dorment, The Telegraph, 19 September 2006 - includes slideshow.

'Leonardo da Vinci: Experience, Experiment and Design' by Adrian Searle, The Guardian, 14 September 2006.

"Leonardo da Vinci was of the few great artists to leave a large quantity of writings; large and small notebooks, pocket books, and separate sheets. They were written in Leonardo's famous mirror-image script, with his left hand. All were left to Francesco Melzi, Leonardo's pupil, friend, and heir, who began the frustrating job of editing the jumble of notes with the aim of publishing them.

Melzi's first and only, project (c. 1550) was to compile a treatise on painting, the Trattato, which he never finished, and after Melzi died in 1570 Leonardo's original manuscripts were soon dispersed. Some given away, some stolen, some lost, some sold. Some were cut up for their drawings. Martin Kemp estimates that about three quarters of Leonardo's manuscripts are lost.

Melzi's unfinished manuscript for the Trattato found its way to the Urbino Library of Federigo da Montefeltro in 1472 ... After Federigo's death the contents of his library wound up in the Vatican Library under the name Codex Urbinas Latinus 1270, or simply the Codex Urbinas where it lay forgotten until 1817, when Guglielmo Manzi had it published."

This and more about Leonardo's work in the 'Leonardo' section of Geometry in Art & Architecture by Paul Calter.

Le macchine di Leonardo Da Vinci showcases models of Leonardo's machines recreated using materials that were available in his own day.

An article in the New Scientist reports on a study into visual noise at the Smith-Kettlewell Eye Research Institute in San Francisco which seems to have discovered why Mona Lisa's expression seems so alive. Researchers manipulated a digital image of the painting to introduce different effects caused by visual noise and asked 12 subjects to rate the expression in the pictures on a scale ranging from sad to happy. "As would be expected, noise that lifted the edges of her mouth made Mona Lisa seem happier, and those that flattened her lips made her seem sadder. More surprising though, was how readily the visual noise changed people's perception of the Mona Lisa's expression." The online article includes a copy of the pictures so you can see the effects for yourself.

'Noisy secret of Mona Lisa's smile' by Philip Cohen. New Scientist, Vol 44, p.1493.

Amateur historian Maike Vogt-Luerssen believes that she has discovered the true identity of the Mona Lisa, claiming in her book Who is Mona Lisa?: In Search of Her Identity (published in Germany) that she is Isabella of Aragon, Duchess of Milan and known friend of Da Vinci and not the Marquese del Giocondo, as is usually believed.

'Was da Vinci's lover the face of Mona Lisa?' by Tim Cornwall. The Scotsman, Saturday 26 June 2004. (Requires free site registration).

The BBC's Leonardo Da Vinci mini-site includes an interactive tour of how his studio might have looked, as well as a picture gallery of his masterpieces.