During his studies in Hamburg, Piller began working on the Peter Piller Archive, in which thousands of images and photos that he meticulously collected from sources such as magazines, the internet, postcards, and aerial photographs are organized, categorized, and assembled in series. His most important tools have always been his gift for precise observation and a subtle sense of humor, which allow Piller to discover serial, curious, and unusual elements in images that appear extremely banal and trivial, and to relate them to others. These include the aerial photo archive von erde schöner, based on 20,000 aerial photos and categorized into 23 series, which Piller has been working on since 2002. His drawings and his own photographs are also always serial. For example, as part of the series Peripheriewanderungen, which he began in 1994, the artist wandered around places and subsequently made drawings and photographs of his walks. The drawings in particular are strongly associative and reflect personal impressions and emotions triggered by the walks rather than being actual documentations or maps. For the series behind time (2017), Piller traveled to various places around the world to observe and photograph rare and special birds. However, instead of depicting them in their full glory, as ornithologists would, the artist always shows them at the exact moment they leave his field of view and ironically names the photographs after the name of the species of bird he photographed. Piller is currently engaging with prehistoric cave paintings that were created in southern Europe during the Ice Age, before humans became sedentary. On this topic as well, he has collected hundreds of photographs and scans from various European libraries, and has taken photographs and made drawings on dozens of trips to southern France and northern Spain.