Architecture: Through a glass, lightly: The new Garden Building at St John's College, Oxford, is inspirational, says Jonathan Glancey

Sometimes you come across a new building that you feel marks a turning point in the story of architecture. It is most likely to be wilful, heroic or outright rebellious: think of the Pompidou Centre by Piano and Rogers, the Neue Staatsgalerie, Stuttgart, by Stirling Wilford, and the Louvre pyramid, by IM Pei. All three have been revolutionary, generated heated debate and been copied and reinterpreted by lesser architects worldwide.

The new Garden Building at St John's College, Oxford - by MacCormac, Jamieson and Prichard - is equally revolutionary, and should have a powerful impact on the development of contemporary British architecture. Yet here, the radical impact of the thinking underpinning the designs is softened by the materials the architects have chosen - brick, stone, timber, polished concrete - and by the historical references found at every twist and turn. Here the keen architectural eye will detect hints of Hardwick Hall (the great Derbyshire Jacobean mansion designed by Robert Smythson), of Sir John Soane's legendary interiors at the Bank of England (long since destroyed), of the hands of the maverick Venetian architect Carlo Scarpa and of the great Frank Lloyd Wright.

But this is no pot-pourri of architectural references: Richard MacCormac and his team have successfully harnessed their delight in historic buildings with their own belief in rational, yet humane, Modernism.

The importance of this new range of collegiate buildings is their successful fusion of history and modernity and of art and architecture without compromise and without loss of faith in progress. In recent years, an increasing number of architects have been turning to their history books to produce what are meant to be literal, but what turn out to be ersatz, copies of 18th-century country houses and town halls. Such work is rarely convincing. In any case, we do not live in the 18th century. Other architects, working in a Post-Modern idiom have toyed with history as if it were no more than a child's toy box, producing such nonsense as the extension of the National Gallery.

It is easy to understand why architects and their clients have sought to dredge the pools of history, but it is upsetting that so few have sought to interpret the past, to use it to give new meaning to the present. The buildings at St John's show that past and present really can work together. References here to Sir John Soane or Smythson are not gratuitous, but a sophisticated play that makes functional sense.

On a prosaic level, the new building is a complex of student and college rooms. The range has been shoehorned into a relatively small back-of-college site, which means that the building is tightly packed and densely occupied. This works to its advantage, as Oxbridge colleges have always been a lovely mix of near-claustrophobic cloisters, courtyards and passages giving on to great open green spaces and romantic lawns and gardens. The students are housed above ground in towers that call to mind those of Hardwick Hall. Rooms are reached by modern spiral stairs elegantly engineered by Price and Myers. Lecture and conference rooms, concert hall and dining rooms occupy magical saucer-domed spaces (based on Soane's Bank of England interiors) below. They are part of an undercroft, an underworld that is nevertheless full of light, diversion and delight.

Nowhere has the college asked its architects to penny-pinch. This does not mean that Jeremy Estop, the project architect or his builders, Try Construction, have spent lavishly on marble floors and gold-plated door handles - far from it - but quality of thought and materials is evident wherever one turns and throughout every considered detail. This is a solid building; so much so that conference rooms boast stone floors. And throughout, materials are handled with a boldness and assurance that one rarely comes across in contemporary British architecture. Here, one experiences the same kind of delight that one has in, say, the country houses and banks of Sir Edwin Lutyens. MacCormac and his team have shown how Modern architects can learn to feel for materials with the same evident joy as their Edwardian predecessors. St John's is both solid and energetic, anchored by history and elevated by leaps of the imagination.

What is most delightful is the way in which MacCormac has brought the work of two contemporary artists into the building seamlessly. The glass walls that march around the undercroft courtyard - where entrance is gained to the meeting rooms and theatre - are a small triumph. These are the work of the glass artist Alexander Beleschenko, a painter who trained at Winchester and the Slade before turning to glass about 10 years ago.

Beleschenko's glass walls are made of of thousands of individual pieces of hand-made and hand-treated glass; they form translucent and transparent walls, bringing light and a lightness of touch into the densest part of the Garden Building. Beleschenko proves that art into architecture does not have to be mere tokenism (as in the 'token Henry Moore' syndrome). His glass is a part of MacCormac's architecture and each gains from the other.

The gate leading from the new range, through a medieval wall, and into the college garden is a second 'artwork'. This is by the jeweller Wendy Ramshaw and, as you might hope, is a finely honed piece of jewel-like ironwork that is far from being decorative whimsy. At its centre, at eye level, is a double-lens through which the whole of the Garden Building is framed.

Both artists were commissioned through a competition organised by the Public Art Commissions Agency. This spirited body, based in Birmingham, is directed by Vivien Lovell. Ms Lovell worked for some years as the arts officer for the London Borough of Tower Hamlets; she remembers trying to convince Richard MacCormac 10 years ago to bring artists into the building process. The collaboration has been a long time coming, but it has been more than worth the wait.

A development of an earlier and successful range of buildings at Wadham College, a matter of yards away, MacCormac's Garden Building at St John's offers a way forward for architects, clients and a public looking for design that combines history, craftsmanship, art and pushes the boundaries of architecture. The Roman architect Vitruvius said that good architecture offers three essential qualities - commodity, firmness and delight. St John's has all three.

(Photographs omitted)