Gerhard Dangel and Hans W. Schmitz have created the Gesamtkatalog der europäischen Aufnahmen 1904-1932 für das Welte-Mignon Reproduktionspiano have written an impressive work. In addition to extensive information on the music rolls, it contains many background details on music roll production. As there was never a complete catalogue of all Welte rolls, this work is all the more valuable - not only for collectors, but also for those who are interested in Welte's reproduction titles.