A chance find at a flea market in the 1970s led to the genesis of a unique collection that meantime embraces more than 500,000 photographs. Today Ruth and Peter Herzog are among the most important photograph collectors worldwide. The holdings date from the early days of the technology, invented in 1839, and extend into the 1970s. They include not only the famous pioneers of the medium, like Nadar and Eadweard Mubridge, but also so far less known or anonymous photographers. The publication provides the first comprehensive portrait of this fascinatingly diverse collection, which since 2015 is being conserved and scientifically appraised at the Jacques Herzog and Pierre de Meuron Kabinett in Basel. Thematic focal points are presented on the basis of about 300 selected objects. The texts focus on major themes of photography such as its tense relationship with art or that between photography and historiography.