The private library of architect Friedrich Gilly, acquired by the Bauakademie in 1802, was considered lost since World War II. However, a representative part of this collection has now been identified in the library of the University of the Arts Berlin. As part of a research project, the provenance of these books has been traced. A comprehensive overview is now available, which scientifically analyzes and comments on the historical Gilly collection. It is contextualized within the architectural discourse of the 18th century shaped by the Enlightenment.