A new type of architecture has emerged in the last ten years, the iconic building. Driven by commercial forces and the need for instant 'brand' recognition, these buildings have to be both provocative pieces of surreal sculpture, and practical, designed to appeal to a diverse audience without recourse to religion or ideology. Such contrary demands have propelled the architect towards a new convention: the enigmatic signifier, which suggests many meanings without naming any of them. Some of these buildings, analysed here by Charles Jencks with a response from Paul Finch, are successful creations, while others are malapropisms that make the public wince. Charles Jencks divides his time between lecturing, writing and designing in the US, the UK and Europe. Paul Finch is editorial director of the publishing group EMAP Construct and was formerly editor of the Architects' Journal.