Big business indeed. The most enduringly successful of the Smithsons' buildings, it is also the most conservative. Essentially it is the American idea of the tower-and-plaza, adapted to the tight scale of St. James, the heart of London's traditional clubland. This cluster of three miniature skyscrapers with their cutaway corners and clip-on panels of fossil-rich Portland stone is rather charming in its self-effacing way. By this time the Smithsons were rediscovering the merits of medieval streets and alleys, and the public route they designed through the complex is not a bad stab at updating that tradition.