Merz Telescopes: A global heritage worth preserving

Introduction: the role of Merz telescopes in Italian astronomy - by Ileana Chinnici.- The Merz Company: a Global Player of the 19th Century - by Jurgen Kost & Gudrun Wolfschmidt.- 1850-1900: The Era of Very Large Refractors - by Paolo Brenni.- The maker and the scientist: the relationship between Georg Merz and the Jesuit astronomer Angelo Secchi - by Ileana Chinnici.- Visual double stars measurements with Merz refractors: some statistics - by Giuseppe Massone.- Padua Astronomical Observatory and Merz Workshop: a special connection - by Valeria Zanini.- Merz instruments at Naples Observatory -by Mauro Gargano.- Merz Telescopes at Brera - by Mario Carpino.- Merz telescopes at Rome Astronomical Observatories - by Aldo Altamore & Francesco Poppi.- Merz Telescopes at Catania Royal Astrophysical Observatory - by Andrea Orlando.- Appendix - A list of surviving Merz telescopes outside Italy - by P. Brenni and Ileana Chinnici.