Picture our Lord as a red lobster

If Sir Thomas Browne of the Religio Medici and Robert Burton of The Anatomy of Melancholy had got together with their contemporary, the emblemist George Wither, and that unlikely combination of learned 17th-century obfuscators had been able to call on the services of a photographer and sensitive colour reproduction (not easy in 1640), they would have produced a book such as this remarkable compilation for the J.

Paul Getty Museum, Los Angeles. Lucia Impelluso wrote it, or more accurately put it together, Stephen Sartarelli translated her Italian, and for Pounds 17.50 its 378 pages - every one of them with large or detailed inset illustrations in full colour from Old Master paintings - represents very fair value. The question has to be asked, however: what is it all for?

Impelluso's two-page introduction pulls off a brilliant bluff. It is 1749 and Georges-Louis Leclerc, Comte de Buffon and director of the Jardin des Plantes, is sending the first of 44 volumes of his encyclopaedic Histoire Naturelle , a tremendous catalogue of plant and animal life forms, to the press. Ah! But stop! The Count has missed out on pre-encyclopaedic science and the symbolism underpinning a natural world, where everything was charged with double or triple meaning. Impelluso's volume, though not much larger than pocket size, is intended to recover what de Buffon lost: the world of wonderment, the symbolism that was essential for so long to humanist culture. For anyone studying Renaissance art, it offers a revelation of half-hidden subtleties; and because the author never assumes a Christian background in her readers, the non-religious will find it helpful.

Symbolism is the art criticism of the conspiracy theorist. Nothing in a painting means exactly what it seems to mean. There is a hidden significance behind everything and the wise will elucidate for the ignorant; it is rather like structuralism applied to English literature, very human and subjective.

The illustrations are divided into seven chapters. There is no text in the ordinary sense of the word; it is a book to be looked at rather than read.

Each chapter - "Plants", "Flowers", "Fruits", "Land animals", "Flying animals", "Aquatic animals", "Creatures of the imagination" - has an introductory page. Then the paintings, usually Italian or Flemish from between 1400 and 1650, are printed in a wide white mount for notes, with lines pointing down from the explanatory note to details such as a griffon dog, a myrtle bush or a fly. Each page is a revelation game to be teased out by following the directional lines; bliss for a lazy reader and a mine of interesting but scattered and often disputable information.

For instance, under "Rabbit", the animal is shown in Carpaccio's Birth of the Virgin (1502-07) as a symbol of fertility. So why, in Mantegna's Prayer in the Garden (c 1460), does one rabbit allude to the souls striving for God, while three other rabbits, ignored by Impelluso, are ambling down the road to meet Judas and the Roman soldiery? If a partridge symbolises intemperate lust, because the male was supposed to smash eggs to stop its mate wasting time sitting on them when it could be mating, why is a pair of partridges painted into Titian's Annunciation (c 1535)?

Explanations are possible and that is part of the intellectual game.

Impelluso is doing a real service by setting up uncertainties. That red lobster next to a bunch of grapes in Jan Davidsz de Heem's Still Life with Fruit (1648-49) refers to Christ's resurrection. Try working that one out. There is a perfectly convincing parallel.

Timothy Mowl is reader in architectural and garden history, Bristol University.