Jacques Rosenthal's (1854-1937) antiquarian bookshop, founded in Munich in 1895, was one of the most important antiquarian bookshops in Germany and Europe until the end of the 1930s. It had business connections with the world's leading antiquarian bookshops and auction houses, libraries, art dealers, and private collectors. In December 1935, due to pressing economic circumstances and the increasing exclusionary measures of the National Socialists, the company had to be sold by the Jewish owners to an employee of the company, the antiquarian Hans Koch (1897-1978). Koch continued to run the company under its previous name, albeit of diminished importance, until 1977.
For the period of Jewish ownership from 1895 to 1935, as well as for the period thereafter until 1977, there is a continuous closed series of hand-annotated sales catalogs and sales lists, as well as a number of auction catalogs. These are personal copies of Jacques and Erwin Rosenthal as well as personal copies of Hans Koch. The annotations provide information on prices achieved and purchasers and thus represent an important source for provenance research. It is a singular tradition for the entire German antiquarian book and art trade.