The project »Letters of Carl Humann (1884–1895)« aimed at taking this collection as a case study for investigating the role scientific communication had on the development of archaeology at the end of the 19th century. Humann, best known for the rediscovery of the Great Altar in Pergamon, was an amateur archaeologist, an architect and an engineer. The letter collection, now in the Staatliche Museen in Berlin (SMB), contains nearly all letters Humann wrote in the last 12 years of his life, in total over 1700. In the course of the project, the letters were all digitized, transcribed, and saved in the database of the Berlin Museum, together with the transcriptions and abstracts of the letters. From this pool, selected letters will be published online on the museum’s website (www.smb-digital.de) for a broader audience. The results of the project will be presented by the author in a commented monograph of the collection. Humann’s letters provide a detailed insight into the life of an archaeologist at the end of the 19th century, a period when ›big digs‹ started on the West-Coast of Turkey. Surprisingly, Humann used the letters only rarely to communicate or discuss scientific problems, but mainly to report to the authorities, to formulate applications and queries, and to organize his endeavors in Turkey. Scientific communication happened mainly directly on site – naturally we are not informed about the content of the discussions. What the letters do in this regard is to give us the invaluable opportunity to look ›behind the stage‹, especially when he planned his extensive visits of Osman Hamdi Bey, the highest administrator of antiquities in the Ottoman Empire, or when he pulled the strings of his network of scientists, friends, and family members to find support for his excavation projects. Unlike any other documents the letters inform us in an unfiltered way about processes and decision making. In regard of general archaeological activities, the letters are an invaluable source of information. Hitherto largely unknown was Humann’s influence on other large excavation projects, foremost his excavations of Magnesia on the Maeander (1890–1893) which evolved into an archaeological role model, especially for the Austrian excavations of Ephesus. It was Carl Humann who purported the scientific ideas and the orientation of the excavation, especially in regard of the focus on the public squares in Ephesus which should be determining for the ›big dig‹ long after his death in 1896. The study of the letters also revealed details about the location of a late antique fountain at the harbor street of Ephesus (disassembled in 1895), important for our understanding of the late antique town. In addition, topics unrelated to archaeology came to light e.g. that Humann was responsible for a wine press in Izmir, he was heavily involved in the trade of emery – including contacts to his business partners S. Seeligman and S. Oppenheim from Hannover – and he was a renowned expert and trader of ancient carpets.