A solid wall consisting of courses of red bricks, a double layer of reflecting glass or a rear-ventilated skin of ornamental metal sheeting: modern facades exhibit an almost unlimited range of materials, forms of construction and appearances. In this issue, a library in Spiez, Switzerland, is distinguished by a modern ­timber outer skin, a material that is nevertheless in the local, rural tradition (page 494). In contrast, the stone outer wall of a housing development in Hangzhou, China, radiates a sense of solidity and reliability (page 525).

The warm texture of the brick facings of a housing block in Santiago, Chile, are contrasted with the strict lines of the prefabricated metal window elements (page 500), while the perforated, corrugated copper facades of a new sports hall in Villach, Austria, are like a semi-transparent veil drawn over the building (page 530). In an office complex in Geneva, the outer skin combines design elegance with the latest technology (page 519). Here, the triangular elements, set at a slight angle, catch the light kaleidoscopically, lending the closed cavity facade a crystalline appearance.