Thames & Hudson £19.95 pp384

Can there be anyone out there who needs help identifying the subject of the Portinari Altarpiece? On the other hand, you probably can’t grasp the meaning of it all immediately. Who, for example, are the variously sized people on the side panels? And just why is the still-life of flowers and wheat so prominent in the foreground?

Help is at hand. Two pages of How to Read a Painting are devoted to an interpretation of just this triptych by the Netherlandish painter Hugo van der Goes (c 1440-1481). The book tells us that the picture (now in the Uffizi gallery in Florence) was commissioned by the Italian banker Tommaso Portinari, the Medicis’ representative in Bruges. He is the man praying on the left-hand panel with two of his sons behind him. His wife, with their daughter, prays on the right-hand side.

The Portinaris are accompanied by their patron saints. On the left, “Doubting” Thomas holds the lance that killed him, while Antony Abbot is identified by a stick or crutch and the bell that helped him drive off evil spirits in the desert. On the right, Margaret of Antioch holds a book and a crucifix while treading on a dragon’s head. Mary Magdalene, meanwhile, displays the jar of ointment with which she once anointed Christ ’s feet.

The setting is the grounds of King David’s palace, now ruined (there is no glass in the windows), part of which is used as a stable. The carved harp above the door of the main building identifies its original occupant while stressing the link between the old Jewish religion and the new, the shepherd King David and the Messiah, Jesus Christ.

Christ’s sacrifice is called to mind by the wheat sheaf in the foreground of the central panel. It signifies the bread broken at the Last Supper, and thus the body of Christ. (The angels are dressed in priests’ vestments to emphasise this link with the Eucharist.) On the other hand, the flowers in the two vases at the bottom of the central panel draw attention to Christ’s mother. They variously signify the Virgin’s purity and the “ Seven Sorrows” she was born to endure. One of them was the Flight into Egypt that you can see taking place behind St Antony’s head on the left-hand panel.Indeed, the marvellously observed winter landscape in the background is full of similar scenes related to the Nativity. On the right, to the left of St Margaret’s missal, are the Three Kings preceded by an envoy and followed by a retinue that includes two camels. To the right of the shepherds in the central panel they are shown again, startled by the news that an angel has brought them.

The painting is huge (the central panel alone is more than 10ft wide). But the illustration in the book is even smaller and, in any case, not every detail is explained. Nor is the symbolism explored as searchingly as it might be. The key to the most profound meaning of the altarpiece may well be St Margaret of Antioch, the saint in red on the right, and the protectress of all pregnant women. When closed, the triptych reveals an Annunciation painted on the back of the two side panels. Perhaps, then, the true subject of the painting is not so much the Nativity as the Virgin’s experience of pregnancy and childbirth and her intercessory role, as Christ’s mother. This interpretation seems more likely still if we remember that the altarpiece was originally made for a hospital chapel.

The book doesn’t tell you everything. But it does help you understand and appreciate the painting more than you would have done without the information it provides. The same is true of the 180 or so other pictures it discusses. All of them date from the period between Duccio in the 14th century and Goya in the early 19th. The meaning of most of them is, therefore, conveyed in a language that was then common to the artist and his public. We don’t share this language any more, but we can learn it so that many of the greatest European paintings will once again tell us more than an Estonian detective movie with the subtitles removed.

Bear in mind, however, that the book won’t help you to “read” every painting you come across from now on. By Goya’s time the most interesting and original artists were no longer interested in this particular kind of symbolism or any kind of allegory. Clearly, the “meaning” of a view of the Seine by Monet — if there is one at all — is quite different from that of the landscape in the Portinari Altarpiece.

And what is the “meaning” of a composition by Mondrian that consists only of vertical and horizontal lines, black, white and the primary colours? Such an abstract painting was made when most artists disapproved of every sort of narrative, whether symbolic or not. Today, however, it looks as though art loaded with meanings is back — even if those meanings are too often trivial, tired, tendentious, self-congratulatory or concerned with the definition of art itself. I refer you to Marcel Duchamp’s Fountain, so recently in the news, or, God help me, Tracey Emin’s Bed. But don’t expect this book to tell you how to read them.

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