Classification and qualification seem almost to be the enemy of artistic endeavour. Yet in The Natural History of Vedovamazzei, the curator Mirta D"Argenzio has produced an elliptical collation of the artists" ideas and hopes that offers a remarkable insight into a rarely defined world, that of Vedovamazzei"s creative process. Simeone and Stella were lovers, from Naples. They were, and are, artists, painters, sculptors. As a matter of course they sketched out ideas in drawings and watercolors, produced cartoons for future projects, dallied with line and colour for experimental concepts. Some of them didn"t work or were put away for another day. These sketches, sometimes no more than doodles or jokes, were also their means of communication when one was away, so that at any moment, on their return, they would find a scrap with an illustration to muse over pinned to the wall. Mirta D"Argenzio, the art historian and curator, came across these fleeting memoranda and resolved to make sense of them, like an Egyptologist deciphering hieroglyphs or an entomologist ordering the development of the Wing-tailed Cabbage White. She set about classifying them into an almost scientific order, from their larval forms through the pupae to the first spread of wings. She has produced a collection of the sketches in eight sections that makes up a visual record of the nascent ideas of Vedova and Mazzei, even in the 21st century cognisant of the traditions of Leonardo. The result of her work is as if one were treading the hallowed halls of the Natural History Museum, with its polished cases of botanical and insect collections, minutely marked and classified by the scientist"s copperplate hand. It is a dazzling display.