The gta Archives mainly hold legacies as well as various archival collections. Famous and important architects are represented here, among them an important number of 19th-century architects such as Gottfried Semper (with the Semper Archive) and his circle, and architects active around the turn of the 20th century (Karl Moser, Gustav Gull, and others), as well as Swiss pioneers of modern architecture such as Hans Hofmann, Alfred Roth, Otto Rudolf Salvisberg and Hans Schmidt, all of these with important holdings.
In addition, gta Archives also hold the CIAM Archives – the complete documentation of all the CIAM Congresses held before and after World War II – as well as the estate of famous art historian and CIAM general secretary, Sigfried Giedion. In recent years new acquisitions have increasingly included the estates of architects who were active in the second half of the 20th century or are still practising today (Fritz Haller, Ernst Gisel, Otto Glaus, Rudolf Olgiati, Lisbeth Sachs, Albert Heinrich Steiner and others). The separate plan collection comprises about 3,000 individual items, and the photo archive roughly 35,000 items.
At present, separate descriptions are being compiled of each body of documents, including detailed information and a selected bibliography. These are written by gta Archives staff members and by external researchers. The following entries (all in German only) have been completed and are available at a click on Gustav Ammann, Paul Artaria, Theodor Fischer, Sigfried Giedion, Otto Glaus, Gustav Gull, Lux Guyer, Hans Hofmann, Hans Leuzinger, Hannes Meyer, Otto Rudolf Salvisberg, Otto Schäfer & Martin Risch, Franz Scheibler, Hans Schmidt, Claude Schnaidt, Jakob Stamm, Gebhard Utinger, and CIAM Archives.