The terms "vertical extension" and "steel construction" have always been closely linked. The enormous capabilities of steel, since its introduction as a building material over 100 years ago, have enabled constructions of unprecedented lightness and span, challenging traditional building knowledge. The vertical "continuation" of historicist principles at the beginning of the 20th century could only be realized through steel construction. The vertical extension exemplifies the tension between technical progress and architectural ideals. In the second half of the century, the display of steel structures served to detach from existing buildings. With the turn of the millennium, the rediscovery of the metamorphosis of buildings returned to concepts of reform and principles of completion. This new book of...