Old and new find winning formula

Summer is the silly season for the art world, which moves to the rhythms of wealthy collectors. While they sun themselves in St Tropez, the galleries back home put on group shows of minimal commercial risk, mixing old stock with emerging artists.

Fiction, happily, is better than most exhibitions of this type, bringing together the work of top draws such as the American Ed Ruscha, the Brazilian photographer Vik Muniz and the Belgian painter AlÀs, with new talent from Britain, Germany and Argentina.

The aim, notionally, is to investigate the idea of truth in painting and photography. The theme is of limited interest.

More interesting is the work. Cieslik and Schenk, a D¸sseldorf-based duo in their early thirties, create detailed computer-generated images of empty, alienating urban scenes.

In one, a scene after a riot or large public gathering, the metal barriers and litter have been arranged into a hurdles track running down the road, implying perhaps that the street is always a location for communal but faintly sinister play.

The question this work raises is not one about truth, but about how the art world will assimilate digital art work - as captivating as these images are, they are similar to the many created by computer-games designers and other digital workers everyday. Which is art and which isn't?

Tim Braden will not suffer such problems. His beautiful and delicately ethereal paintings depict scenes culled from literature or his past.

The large work here shows a grand room decorated in the style of the high bourgeoisie, painted, unusually in watercolour on canvas. This gives it an insubstantiality akin to the lightness of human memories.

The best piece by the old guard is also one of the oldest: a series from the late Sixties by Ruscha of black-andwhite photos of parking lots taken from the sky, a vantage point that reveals the accidental patterns created by our sterile and utilitarian architecture and urban planning.

Until 4 September. Information: 020 7409 3344.